ILLUSTRATION

by 1910 the rapid advance in the various methods of process reproduction had resulted in the complete liberation of the draughtsman from any of those con- siderations which had limited him in the days of the reproductive wood-engravers. this new freedom was in some ways a misfor- tune, especially as photography made it possible to reduce a design to any convenient size, so that the artist too often forgot altogether that his object was to decorate a book. the perfect illustrator is rare, and the most admirable drawings, when they are merely attached to an author’s text, may not be illus- trations at all. | the new interest in typography, stimulated by the work of william morris, but in reaction against the heaviness of his types, has resulted during the decade 1915-25 in an enormous increase in the number of beautifully printed books issued from the press. many of the english editors content themselves with fine typography, embellished perhaps with occasional head pieces and culs-de-lampe, but most of these decorative details are well- conceiyed, and pleasantly arranged with reference to the size of the page and the area of the type. the possibilities of the woodcut have been most fully appre- ciated and exploited on the european continent. its advantage over the intaglio methods, such as etching or copper-engraving, is that the wood block can be printed with the type by a single operation. technically, however, it is a reaction, and the small- ness of its field makes it unsuitable for use in illustrating popular magazines. the efficiency of modern reproduction makes it pos- sible for an artist to design in almost any medium, with the reasonable hope that his intentions shall not be travestied on the printed page. 1 british standard specification for portable photometers, no. 230 (1925). _ beet — _ 2 british standard specification for industrial reflector fittings for electric lighting, no. 232 (1926). ati some notable work.—some of the best examples of the use of the half-tone and line-block processes in england are still to be found in punch, and range from the graceful, elegant manner of lewis baumer and (until recently) of claude a. shepperson, to a sympathetic treatment of proletarian types in george belcher’s reproduced pencil drawings. the ‘‘ sequence picture,”’ influenced by the cinema, but drawing its first inspiration perhaps from caran d’ache, receives competent treatment at the hands of if. m. bateman and “ fougasse.”’? w. heath robinson in known not only as a comic artist of fantastic invention, but as a delicate illustrator of fairy tales. more purely decorative is the work of edmund dulac, who relies, as does also arthur rackham, on the three-colour process. the last three artists named have done much to raise the standard of the illustration of children’s col- oured books. ‘the nursery picture-books of about rgoo, in spite of the previous example of kate greenaway and randolph caldecott, were often crude in colour and ugly in design. — the influence of beardsley is scen in the work of john austen, harry clarke and ‘‘ alastair,” while artists hke h. m. brock continued the hugh thomson tradition. f. cayley robinson and russell flint are perhaps best known for their painting, outside the sphere of illustration, but they have both done good work within it. ethel gabain (mrs. john copley) may be in- cluded in the english school, although her most important lithograph illustrations have been issued by french publishers. two able architectural draughtsmen are e. h. new and i. l. griggs, while frank brangwyn brings to the illustrations of books, such as southey’s life of nelson and kinglake’s eothen, the same power of emphatic statement and grandiose concep- tion as distinguishes his larger work. the early death of lovat fraser cut short a carecr of great promise which, in spite of its brevity, has exercised a far-reaching influence on various british arts. his method of working in flat tones and simple outline was peculiarly suited to modern colour-reproduction, and his example has been widely followed. of the more “ advanced ”’ artists, many of whom have exploited the possibilities of the original woodcut, may be mentioned v. gribble, r. gibbings, paul nash, albert rutherston, ethelbert white, a. buckels and s. gooden. the last-named has done much to revive the use of line-engraving on copper. french workers.—enthusiasm for the original wood-engraving is greater perhaps in france than in any other country, and so much excellent work has been done by this method alone that the chief difficulty lies in the selection of representative names. a more or less homogeneous group is formed by maxime detho- mas, with his dignified line, hermann-paul, with his broad handling and strong dramatic feeling; and carlegle. the well- known edifions cres are decorated admirably by gus bofa, by simeon, by sylvain sauvage, by contel and by daragnes. the last-mentioned artist has used etching as well as wood-engraving, and indeed —now that the chief aim of the woodcut, to harmonise with the printed page, has been generally accepted—there is no reason why artists should not avail themselves of lithography, as does l. a. moreau, or of line-engraving, like laboureur, or of etching, like c. laborde. mention should be made of the colour woodcuts of falke, the work of brissaud, of desligneres, of galanis, whose curious use of white hachures is well known to english amateurs; of raoul dufy, better known in england as a painter; of paul vera, of laboureur, with his curiously effective deformations; of jean marchand, and of raphael drouart, all of whose work goes to make this present epoch of book produc- tion in france a very notable one. germanyv.—germany perhaps more than any other country has felt the iniluence of the most extreme aesthetic theories. the disorder following the war and the sense of humiliation in defeat tended to anarchy and disillusionment in the arts also. an amazing number of fine books has been produced, but the illustrations to some of these are conceived in a slap-dash, sketchy fashion, impossible to harmonise with the necessary orderliness of a printed page. even artists of the standing of lovis corinth and max slevogt sometimes scribble over, rather than illustrate, the works entrusted to them. the mass of modern german 412 work, however, is impressive. a few names may be singled out :— max pechstein, alfred kubin, willy geiger, fritz heubner, julius diez, oskar oestreicher, wilhelm wagner, richard see- wald and george grosz, the last-named being an able artist who exemplifies that curious obsession with sex which characterises too much modern german art. the general standard of book production in germany is higher than it has ever been, and it is from germany that the smaller countries of europe, with the possible exception of a francophil poland, draw most of their inspiration. bibliograpity.—m. c. salaman, ‘ british book illustration yesterday and today,’ studio special winter number (1923); leon pichon, ‘‘ the new book ijilustration in france,”’ studio, special winter number (1924); herbert furst, the modern wood- cut (1924). (j. la.) united states—the comprehensive word “ illustration ” covers two main branches of the art—the self-contained picture and the picture which forms the amplification of a literary theme. in the former, the illustrator is called upon to supply a picture of some situation of life or some theme or fantasy, complete and self-explanatory. in the latter, the illustrator has to embellish sympathetically the meaning of his accompanying text. the subdivisions in both these classes are numerous. ‘the self- contained illustration can be anything from a comic strip draw- ing to a poetic fantasy, but it essentially has to rest on its own individual merits. the illustration which has a literary partner can be anything from an advertising design to the pictorial embellishment of the finest periodical, book or treatise. these are the extremes covered by the word illustration. perhaps the most prevalent and important branch of the art today is the illustration of magazines, books and newspapers. in recent years this art has reached a very high degree of pro- ficiency, both in artistic technique and in the process of re- production. indeed it is probable that the vast improvements in reproductive methods and the refinement of paper have acted as incentives to illustrative artists. illustrations for books, maga- zines and papers should be wedded to the text, and at the same time should extend the meaning of the text by their realistic, artistic or imaginative quality. ‘most illustrations of to-day have realism as a predominating feature; it therefore might be argued that the great advances in artistic photography might supersede the hand-made illustration, but it is not so. the art of the illustrator cannot be dispensed with, for in its best form all the necessary realism is there, plus the almost indefinable pleasure which technique produces on the observer, whether he be an artist or not. the best fiction illustration of the period is perhaps to be found in america. there are several very powerful illustrators in europe, but on the whole the american illustrator excels. amongst the many exponents of the art, selection is difficult, but it is not easy to imagine better or more applicable illustration than the work of dean cornwell in half tone and dana gibson in line—both men being leaders of schools of illustrative thought. the mere mention of these two names makes it hard to refrain from enumerating a host of other most capable wlustrators, but space will not permit. the english counterparts to the above two artists are difficult to select, but the work of frank craig in half tone and of frank reynolds in line have provided some exquisite illustration. the work of all four has allowed artistic technique to help the story and yet not engulf it. they have all been great “ stylists’ and have many followers. this analysis of illustration as an art holds good through- out the world, and in theory has been approximately the same since man became capable of illustration in even the primitive forms. there have naturally been modifications and peculiar- ities in ability and style due to elementary conditions; and there have been differences of technique, due in the main to racial causes. (b. b.) immigration: see migration. immingham, england, a seaport situated on the lincoln- shire shore of the humber estuary, 9 m. 8.s.e. of hull and 5 m. n.n.w. of grimsby, england. constructed (1906-12) by the immigration—immunity great central railway co. (now part of the london and north eastern), the dock comprises a square basin and two long arms (including a graving dock) running parallel to each other on the western side, of a total area of 45 ac., with 5,400 ft. of quayage; the depth (30-35 ft.) is sufficient for practically any vessel afloat. the dock is specially designed and equipped for dealing with the coal, timber, grain and wool trades, and was officially opened by the king on july 22 1912. the area of the dock property, 2: m. in length and t m. in greatest depth, is just over 1,000 ac. with a river frontage of 13 miles. the site was chosen because the deep-water channel of the humber, which lower down runs midway between the shores, here makes an inward sweep and leads right to the dock gates, thus obviating much initial dredg- ing, providing ingress and egress at any state of the tide, and rendering the towage of vessels unnecessary. the original village of immingham lies a little inland, but a new town is growing up near the docks. the grimsby electric tramways have been extended to immingham and, in addition, a light railway runs between the two places. immunity (sce bacteriology, 3.175).—the term ‘ immu- nity ” is used in science in the technical sense. an animal is described as naturally immune against the microbe of disease if the microbe in question cannot establish itself in the organism and as artificially immune if it was naturally susceptible and has been rendered insusceptible. similarly, an animal is described as naturally tmmune against a poison if its organism is naturally proof, and as urtifictully tmmune if its organism has been ren- dered proof against the poison. natural immunity —a few words may ‘be said first with respect to natural immunity against infection. we may at- tribute the fact that the body normally remains free from mi- crobic infection to a conjunction of causes:—first, to the fact that its external and internal coatings furnish mechanical protections against infection (this point need not be further considered here); secondly, to the fact that the body is equipped with special machinery for the destruction of microbes (the nature of this machinery will be discussed below in connection with acquired immunity); and, thirdly, to the fact that certain of the conditions which normally prevail in the animal organism are inimical to the growth of microbes as a whole or at any rate to the growth of certain classes of microbes. of the conditions here in question two which are of quite dominant importance were discovered in the course of researches on wounds carried out in the world war. antitrypsin.—the first and more generally important is the antitryptic power of the blood fluids. such antitryptic power will in every case hamper, and in the ordinary case com- pletely inhibit, bacterial growth. it will achieve this by neu- tralising, in part or completely, the digestive ferments of the microbes which would otherwise convert the unassimilable native albumens of the blood-fluids and serous discharges into assimilable nutrient materials. antitrypsin in the blood fluids will therefore mean for the microbes therein implanted, either, a restriction of their food supply, or complete starvation. the facts, as far as known, all comport with this inference. to begin with, only a few species of microbes (the staphy- lococcus, streptococcus, pneumococcus and perhaps the mi- crobes of all genuinely septicaemic diseases) can proliferate in antitryptic blood fluids. further, these microbes (we may conveniently call them serophytic microbes) produce when grown in plasma (we are here generalising from observations made with staphylococcus and streptococcus) trypsin which quenches the antitryptic power of the surrounding blood fluids and then digests vacuoles in the surrounding clot. again, all serophytic microbes grow very much more vigorously (the streptococcus for example very many thousand times more vigorously) in the blood fluids when these microbes have, by an artificial addition of trypsin, been relieved from the task of themselves producing enough trypsin to quench the anti- tryptic power of the surrounding medium. and finally, all those kinds of microbes which are unable to grow in antitryptic blood fluids begin to pullulate there the moment trypsin is added—~ immuntty and let it be noted here that a spontaneous addition of trypsin occurs regularly in wounds as soon as the emigrated leucocytes are broken down under the influence of bacterial growth and unfavourable external influences. effect of alkaline reaction —again—and here the second of the restraints on microbic growth spoken of above comes into question—in the course of research work on wound infections conducted in the course of the war, it was established, in con- nection with the microbe of gas gangrene, that the prolifera- tion of this bacillus in the blood fluids and serous effusions is inhibited not only by the antitryptic power but also by the normal alkaline reaction of these media. proof of this is fur- nished by the fact that as soon as the alkaline reaction in ques- tion is blunted off by the ante- or post-mortem formation of lactic acid in muscles deprived of their blood supply, or more directly by an infusion of any acid into the blood, the bacillus of gangrene multiplies without restraint. natural susceptibility—the problem as to why a particular animal is naturally susceptible to particular poisons is likewise a chemical problem, but a chemical problem of a different order. formulated in the technical terms which were introduced by ehrlich the problem is that as to why the tissues of the insus- ceptible animal contain no receptors for the poison, that is to say, no organic substratum upon which that poison can anchor itself. this is a question of the aboriginal chemical consti- tution of the body—a question as to why a particular species of animal was constructed of one kind of elements rather than of another. a , acquired immunity—the problem presented by acquired immunity to infections or poisons differs in important respects from that presented by natural immunity. with respect to such reinforcement of the natural resistance it will be well to note at the outset (a) that it can be achieved apart from any violent physiological commotion; () that acquired immunity does not betray itself in any altered habit of body; and (c) that the con- dition may in many cases be present to-day and gone to-morrow. all these facts indicate that the acquired immunity cannot involve anything in the nature of a revolutionary physiological upheaval such, for example, as a fundamental alteration in the blood elements, or a cutting out of receptor elements from cells. anticipating here, we may say that later it will be shown with regard to acquired immunity to infections that this depends upon the development of (wu) increased antibacterial substances in the blood fluid, (6) increased efficiency in the leucocytes and (c) increased capacity for producing antibacterial substances in response to infection. similarly it will be shown with regard to acquired immunity to poisons that this depends upon the ap- pearance of neutralising elements (so-called antitoxins) in the blood coupled with the acquirement of increased capacity for elaborating these elements in response to an incorporation of the corresponding poisons. early doctrines——confining ourselves to the problem as to how the bacterial infections are combated in the organism, we may begin by considering the two chief opposing doctrines which were promulgated, when, under the prompting of pasteur’s prac- tical achievements in the field of prophylaxis, problems of im- munity began to be first seriously considered. these theories included natural as well as acquired immunity. humoral theory—in the theory which goes by the name of the humoral theory, natural immunity is attributed to the bactericidal substances contained in the normal blood fluids, and acquired resistance to the acquisition or increase of such bactericidal power. the general thesis, at any rate, of this theory stands secure. where microbes are killed otherwise than by physical agencies or by inanition, their destruction must inevitably result from some form of chemical action. so, too, the acquisition of greater power of destruction must of necessity be imputed to the achievement of more potent chemical powers. on the other hand, it cannot of course be a priori certain that the antibacterial elements concerned in the destruction of microbes will be found in the blood fluids and only in these. that the blood fluids do, in point of fact, possess bactericidal 413 power was demonstrated by fodor and nuttall, and it was at first thought, though a careful study of nuttall’s results should have prevented this, that such bactericidal action was exercised upon microbes without distinction of kind. later research has, however, shown that the blood fluids are directly poisonous only for certain species of microbes such, for example, as the typhoid bacillus and the cholera vibrio. certain other species of microbes, and in particular the microbes of specifically septicaemic diseases are, as we have seen, serophytic—the number that grow out in serum being as great as the number which grow out in the best artificial nutrient medium. thus, the so-called humoral theory, though itt would account for the organism possessing considerable resistance to typhoid and cholera, leaves unexplained the fact of the normal organism offering very considerable resistance to serophytic microbes. what applies to natural, applies also to acquired immunity. there is nothing to show that increased resistance to serophytic microbes and septic infections generally is accompanied by the development of any bactericidal power in the blood fluids. phagocytic theory.—an_ entirely different conception of immunity is that familiarly known as mechnikow’s theory of phagocytosis. in the humoral theory the problem of immunity is envisaged from the point of view of the bacteriological special- ist and to some extent also from the standpoint of the chemist. mechnikov for his part approached the problem from that of the morphologist who takes the whole field of animal life as his province. his theory of tmmunity therefore starts with the generalisation that the protozoa feed upon the lower forms of life such as microbes. jt further regards the fact that the higher animals have been evolved out of colonial aggregations of pro- tozoa. in every such colonial aggregation certain of the asso- ciated cells instead of becoming specialised persist in the condition of wandering cells. with regard to these free-living members of the protozoal colony mechnikov divined that they function as defensive cells. and he showed in connection with sponges and other invertebrates that these wandering cells collect round invading microbes and other foreign intrusions and that they thereafter proceed to ingest and digest them or, to aid otherwise in their elimination. lastly mechnikov pointed out that the leu- cocytes of the vertebrate were homologous to those wandering cells and performed exactly the same defensive offices. in par- ticular when leucocytes emigrate from the capillaries into a focus of bacterial infection, in the normal case, they follow this up by ingesting the intruding micro-organisms, and killing them intracellularly. natural or native immunity was thus, in the conception of mechnikov, due to efficient leucocytic function- ing; and acquired immunity to the leucocytes having by a process of training (as he called it) acquired a power of more effectively confronting, ingesting and destroying microbes. tclectic theory.—the central tenet of the mechnikov theory—the tenet that the leucocytes play a very important role in the defence of the body against infectton—has now found universal acceptance, but at the same time the doctrine that resistance to infection depends in every case on the action of the leucocytes has proved untenable. in connection with the defence of the organism we must distinguish between (1) defence against infection by serophytic microbes, that is against microbes which like the streptococcus and staphylococcus pro- liferate in the normal serum, (2) defense against infection by microbes which are incapable of multiplying in the antitryptic normal serum but are not directly killed by it, and (3) defence against microbes which are directly killed by the serum. (a) in connection with the first kind of microbe the fact that although they grow freely in the serum and plasma, these are killed in large numbers in the blood and in the serum, when liv- ing leucocytes are added, shows that the cellular elements of the blood here do the work of destruction. (b) in connection with the successful killing of these microbes, the leucocytes must, however, in all cases have free mechani- cal access to the microbes. there would for example be de- fault in this respect if, as would happen in dealing with infected 414 defibrinated or infected centrifuged blood iz vitro, the leucocytes settled to the bottom and the microbes were buoyed up out of their reach in the serum. the same would of course happen iz vivo in all serous effusions. (c) in connection with those microbes which are not directly poisoned but fail to proliferate in the serum, the most important restraining influence is the native antitryptic power of the blood, but once the antitryptic inhibitory action of the blood fluids and serous effusions has been neutralised the leucocytes, even when everything else favours them, will be impotent to inhibit microbic growth. on the contrary as soon as the leucocytes degenerate they will furnish a further quantum of trypsin and in this way directly conduce to the pullulation of all manner of microbes. lastly, the leucocytes do not seem to contribute to the defence of the organism against those microbes which, like the typhoid bacillus and the cholera vibrio, are directly poisoned by the serum. when we implant such microbes into defibrinated blood and then incubate and make microscopic preparations those microbes which are quickly ingested are found intact within the phagocytes while those which are left exposed to the action of the scrum are distorted and dissolved. and again, when living emigrated leucocytes are brought to bear upon typhoid bacilli it would seem that few of the microbes are killed. precisely similar results are obtained with extracts made from leucocytes. it was shown by schattenfroh that such extracts exert bactericidal action upon the staphylococcus and strepto- coccus while they exert no such action upon the typhoid bacillus and the cholera vibrio. and again it was shown by colebrook that the products of inflammation derived from foci of inflam- mation set up by incorporating into rabbits lint soaked in ty- phoid vaccine are powerfully bactericidal for the staphylo- coccus and streptococcus while for the microbes of typhoid and cholera they are not more bactericidal than ordinary serum. this review of the facts shows that only in the case of scro- phytic microbes does the defence of the body depend upon the leucocytes and that when it is a question of defence against the other two classes of microbes (those whose growth 1s entirely inhibited and those which are directly poisoned by the serum) the leucocytes are either impotent or directly harmful. properties of the leucocytes concerned in immuntisalion.— mechnikov originally taught that the leucocytes were attracted to microbes and induced to phagocytose them by the toxin secreted by the microbes; and that there was here only an interaction between leucocytes and microbes and that the blood fluids could be left entirely out of the story. that that doctrine cannot be sustained can be demonstrated by a very simple experiment. , we begin by receiving a sample of blood taken direct from th vessels into normal salt solution. we then centrifuge and recentrifuge in further volumes of this norma! salt solution so as to wash the cellular elements free from all traces of the blood fluids. we then make two so-called phugecvite mixtures com- bining in the one case (a) one volume of a bacterial suspension with (6) one volume of washed leucocytes and (c) one volume of 90-85% salt solution; and in the other case (a) one volume of washed leucocytes, (6) one volume of the same bacterial suspen- sion and (c) one volume of normal scrum. these mixtures are then placed in the incubator and after a suitable lapse of time a sample of each is examined under the microscope. in the first phagocytic mixture—that in which no scrum was employed— the leucocytes have failed to ingest any microbes. in the specimen in which serum has been employed, the microbes have been plentifully ingested. this result depends not upon any stimulating effect exerted upon the leucocytes, but upon the fact that the serum has effected a chemical change—a so-called opsonte change—in the microbes. that this epsonte change docs not in any sense affect the vitality of the microbe is shown in the case of scrophytic microbes by the fact that the serum that exerts an opsonic effect furnished culture medium in which the affected microbes will all grow out into colonies. the blood iluids intervene further in the destruction of microbes in the interior of the phagocyte by combining with them in such a way as to immunity favour their intracellular digestion. this action, which was first described by douglas, is known as the protryptic action of the blood fluids. the living leucocyte can also kill microbes apart from phago- cytosis. the following experiment is instructive. a shallow receptacle is filled with a solid nutrient medium whose surface has been uniformly implanted with staphylococcus or -strepto- coccus. the centre portions of the three cover glasses are thickly carpeted with living leucocytes obtained direct from the blood. we now, after different treatment, impose these cover glasses side by side upon the implanted nutrient surface. in the case of the first cover glass the adhering leucocytes are brought into application in conjunction with the adhering serum; in the case of the second they have been washed free from every trace of serum; and in the case of the third cover glass the adhering leucocytes, instead of being employed living, have been killed by drying. the whole preparation is now incubated at blood heat for 12 hours or more. the microbes will then be found to have grown out forming an uninterrupted sheet of colonies over the whole surface of the nutrient medium except under those areas of cover glasses 1 and 2 which are carpeted with living leucocytes. here the implanted microbes have not proliferated, and micro- scopic examination of the cover glasses shows that where the leucocytes came into action in conjunction with serum the microbes are all lying intracellularly; while where the leucocytes were washed free from serum— the microbes are all lying extra- cellularly. the experiment thus shows that microbes can be killed by leucocytes both intra- and extra-cellularly, z.e., both by phagocytosis and also apart from phagocytosis. this holds true both under the conditions obtaining in this particular experiment, and also in numerous other conditions. that destruction of microbes by leucocytes without the intervention of phagocytosis occurs also very frequently i vive is practically certain. results of experiments——research has thus shown that the destruction of microbes in the body does not proceed only along the lines laid down in the humoral and phagocytic theories. instead of there being, as was assumed in those theories, only one physiological device by which microbes without distinction are killed in the organism, nature would appear to provide ditferent distinctive devices for different microbes. some path- ogenetic microbes are combated by the bactericidal action of the serum unassisted by the leucocytes, others again are pre- vented from proliferating by special agencies, such for example as the antitryptic power of the blood; and again a third description of microbe, the serophytic microbes, are destroyed intracel- ularly and extracellularly by the leucocytes aided, or as the case may be, unaided, by the blood fluids. the above deals only with the normal protective machinery of the body as distinguished from that which comes into play in artificial immunity. in connection with the latter mech- nikov, as will be remembered, taught that acquired resist- ance was due not to any changes in the blood fluids, but to the leucocytes having been subjected to a process of training which gave to them a greater capacity for confronting and ingesting microbes. this doctrine had to go by the board when it was shown in numberless cases that increased phagocytosis goes hand in hand with increasing opsonic power in the blood fluids. i'rom this it was incautiously assumed—though this tenet was never definitely formulated—that the leucocytes con- stitute in artificial immunity an invariable, and the blood fluids the only variable, factor. that the phagocytic efficiency of the leucocytes was also a variable factor was first shown by shattock and dudgeon, who observed that the phagocytic efficiency of the patient’s leucocytes is in many cases of pyrexial infection greatcr than that of the normal man. the phagocytic efficiency of a patient’s leucocytes may also, as was further shown by shattock and dudgeon, be less than normal. these observations have a direct bearing upon mechnikov’s doctrine with respect to acquired immunity, since, in all infec- tions which are associated with constitutional disturbances, antigens from the foci of infection are being brought into immunity operation—in other words the organism is experiencing and is reacting to auto-inoculations. it follows that, conformably with the doctrine of metchnikov, the leucocytes should in every case of pyrexial infection be conducted by successive degrees to a condition of continually increased phagocytic efficiency. instead of that these cellular elements are, sometimes in localised infections, and practically always in streptococcus septicaemia, reduced to a condition of diminished efficiency. artificial immunisation.—we have to consider next how to increase the effectiveness of the anti-bacterial machinery, 7.e., how to produce artificial immunisation against infection. the origi- nal point of departure was the observation that those patients who had contracted and recovered from an infectious disease were thereby rendered proof against reinfection. that obser- vation led, in connection with smallpox, to the adoption ofa procedure for the warding off of the disease. the procedure adopted in various parts of the world and introduced to europe from turkey, consisted in the implantation into the susceptible individual of material obtained from a patient suffering from smallpox. this procedure, which was denoted inoculation be- cause it resembled the grafting of an eve or bud into a new stock, is in reality the parent from which all other procedures of artificial immunisation are derived. what required still to be done was to purge inoculation of its dangers and to regulate the immunising stimulus. this was successfully done in jennerian vaccination. but the achievement of jenner was in pointof fact purely empirical. pasteur’s work.—after jenner came pasteur and with pasteur scientific methods are for the first time brought into appli- cation in connection with prophylactic inoculation. his initial achievement was to recognise that the essential in jennerian vaccination was that for a virulent infective organism obtained from actual cases of smallpox there has been substituted an infective organism which by the operations of nature—to wit by transfer to the cow—had been attenuated in such a manner as to render it non-lethal for man. by the exploitation of that general principle, by the employment of pure culture and by a technique of artificial attenuation adapted with infinite resource to each separate case, the whole series of pasteurian successes in the field of artificial immunisation were one after another achieved. artificial immunisation was not, however, purged from all its risks by the procedures of pasteur. it had not yet been transformed into a scientifically regulated procedure. the pasteurian vaccines were in point of fact standard- ised only thus far that recourse to attenuation placed in each case a certain limit upon the proliferation of the vaccinating material in the organism of a normally resistant man or animal. standardisation.—a great step in advance was taken when it was established in connection with anti-typhoid inoculation that the antigen required for the setting in motion of the machin- ery of immunisation can be furnished by the incorporation of sterilised microbic cultures. and further, important steps to the achievement of a standardisation of bacterial vaccines were made when a technique for the enumeration of the microbes in bacterial suspensions was devised, and when it was recognised that weighed quanta of desiccated and powdered bacterial sub- stance could be employed in cases where, owing to the felting together of the microbes, enumeration of the microbia! suspension was impracticable. the counting of the microbes or the weigh- ing of the bacterial substance is, however, only a means to an end—the standardisation of a vaccine, e.e., the determination of the doses which will give the best “‘ curve of immunisation.” | the curve of immusisaiion.—the expression curve of timmunisa- tion calls attention to certain fundamentally important points in connection with the reaction of the body to the incorporation of vaccines. in the pre-pastcurian and pasteurian periods, when ideas about the nature of immunising response were still vague, it was assumed with regard to vaccines that they produced their effects only after a certain incubation period (ordinarily only after 10 days). and it was further taken for granted that the curve of immunisation would from the beginning move always in the upward direction. when, however, immunisation 415 curves came to be constructed (and this was done first in con- nection with anti-typhoid inoculation) unanticipated features revealed themselves and in connection with these also time- relations which did not conform with expectation. negativeand positive phases and practical importance of these. — in what may be called the normal case—i.e., in the case where the dose of vaccine inoculated is sufficient to produce an appreci- able constitutional disturbance, a bi-phasic curve of immunisa- tion is obtained. for 24 or more hours after the inoculation the antibacterial power of the blood is reduced. this—the so- called negative phase—is followed by a phase of increased antibacterial power—the so-called positive phase—which may last for one or two or a number of days as the case may be. after this the antibacterial power falls away gradually to a level only slightly higher than the original normal. but despite this there would seem to persist in the organism (and this would seem to be the chief profit from inoculation) a power of making more rapid and more ample immunising response to any subsequent incorporation of antigen whether in the form of a subsequent inoculation of a similar vaccine, or actual infection. when, instead of a quantum of vaccine which produces a con- stitutional disturbance, a‘smaller dose is inoculated, the negative phase is elided and a positive phase is well developed already 24 hours after the incorporation of the vaccine. and, finally, when excessive doses of vaccine, such as produce very severe constitutional disturbances, are incorporated, the negative phase may be correspondingly intense and may persist for many weeks, these facts have an important bearing upon prophy- lactic operations; they must also, as reflection will show, have an importance in connection with the immunisation procedure to which horses are subjected with a view to their producing antibacterial and antitoxic sera. again substantially the same relations as between the quantum of vaccine inoculated and the type of response elicited, obtain in the case where vaccines are inoculated into patients who are the subjects of infection. but in that case the conditions are so far different that we have to consider in each case two quanta of antigen: that administered in the vaccine, and that already contained in the patient’s organism. where a patient is the subject of only a minimal infection, we may employ doses of vaccine nearly as great as those employed for the prophylaxis of healthy men. where a patient is heavily infected, we are restricted to the employment of minimal doses, and finally, when the patient is already labour- ing under an excessive infection, the injection of vaccines can only do harm. the principle that the kind of response, and the amplitude of the reaction, and the time-relations of the phases are in each case a function of the quantum of antigen brought into appli- — cation is found to apply also to the case where the vaccine is added to the extravascular blood. we obtain 7 vitro every variety of effect according to the dose of vaccine brought into © application and the time for which it operates upon the blood— the effects varying from an instantaneous increase of bacteri- cidal power to a loss of most of that destructive power. and further different effects are obtained according as we select now one and now another method of testing. we obtain for example one result when we measure the bactericidal power of the whole blood; another when we measure the opsonic power of the serum; a third when we measure the phagocytic efficiency of the leu- cocytes. it must remain for the future to unravel these compli- cations. for the moment the essential point to note is that the machinery of immunisation which was supposed to be con- structed upon a very simple—and one may add foolprooi—plan is in reality built up of very delicate and complicated elements. the lessons which can be drawn from immunisation curves may now be summarised. the first of these is that excessive doses of vaccine may delay and possibly interfere with the pro- phylactic response, and further that such excessive doses of vaccine administered to patients suffering from an infection may definitely aggravate their condition. other important lessons are that when appropriate doses of vaccine (i.e., doses which are not followed by a negative phase) are administered, prophy- aio lactic effects may be obtained almost immediately after inocula- tion. and further it should be possible to arrest a general infection by inoculating in the incubation period and then employing a reduced dose of vaccine. in connection with this. attention may be directed to the statistical records of haffkine’s anti-plague inoculations in the byculla jail in the city of bombay, and to the cases put on record by miss corthorn. the records of the byculla inocu- lations make it probable that a prophylactic effect was here exerted already 24 hours after the vaccine had been given. and the cases recorded by miss corthorn seem to make good that attacks of the plague were not unfrequently aborted by the inoculation of the vaccine (see plague). further evidence showing that immunisation develops very rapidly after the inoculation of an antigen is furnished in the work of von pirquet. if a first implantation of vaccinia is fol- lowed by similar implantations on successive days, the response to these latter differs from the response made to the first. ‘this altered clinical response—which would appear to indicate a more rapid destruction of the later implanted infective material— was described under the name of a/lergy. it was further shown by von pirquet in connection with the inoculation of foreign serum that the supervening clinical reaction—which appears to indicate the throwing out of that foreign serum from the blood— is accelerated when the injection of serum is made into an or- ganism which has been before subjected to that procedure. the interval between the injection of the foreign serum and the clinical manifestations associated with its elimination from the blood (normally 10-14 days) may be reduced to a very few minutes. further questions inconnection with artificial immuntsation.— a series of further questions in relation to artificial immunity have to be considered (1) are there agencies other than vaccines proper—in other words, other than living or dead microbes or substances derived from the bodies of microbes—which will afiect the bactericidal power of the blood and leucocytes? (2) again are the antibacterial substances in the serum specific in the sense of operating only upon one particular variety of microbe or are they non-specific? (3) further, will leucocytes which have acquired increased phagocytic efficiency, ingest more actively only one particular species of microbe, or all microbes without distinction? (4) finally, what are the cells in the body which elaborate the anti-bacterial substances? all these questions are intimately linked up. non-bacterial v accine—in connection with the question as to whether there are agencies other than vaccines proper which can increase or, as the case may be, diminish the bactericidal power of the blood, it has been shown that the infliction of burns increases the bactericidal power of the serum for the an- thrax bacillus. this increased bactericidal power is no doubt referable to an absorption into the blood of disintegration products derived from the burnt tissues. again, it has recently been ascertained that increased bactericidal power can be de- veloped in the blood i vitro, by adding to it foreign sera and also non-foreign sera which have been artificially altered by heating to 60° c. lastly, it has been shown in connection with the irradiation of the skin with ultra-violet light, the light of the electric arc and sunlight, that by these agencies also the bactericidal power of the blood is increased, such increased bactericidal power depending upon an increased phagocytic power of the leucocytes and also an increased antibacterial power in the serum (see heliotuerapy and public hrealtm). it is not yet known how irradiation produces these results, but the consideration that radiations such as are here in question are much more likely to act by breaking down than by building up albuminous substances, taken together with the fact that increased bactericidal power is achieved only with a certain quantum of irradiation and that the blood suffers deterioration when larger doses are employed, would seem to point to the con- clusion that we are here, in each case, dealing with effects produced by the absorption into the blood of an antigen in the form of disintegration products generated by the irradiation. immunity specificity —the non-bacterial antigens which have been under discussion above occupy at present a position apart in the respect that it would generally be held with regard to these that they might quite likely evoke a non-specific immunising response; whereas it would be generally held that bacterial vac- cines would produce only specific immunising response. but against this there is conclusive evidence to show that bacterial vaccines also evoke non-specific immunising response in the form of increased bactericidal power in the blood, increased phago- cytic efficiency in the leucocytes and sometimes also increased antibacterial power in the serum. thus, for example, by the incorporation of staphylococcus the blood can be rendered more bactericidal for streptococcus. ‘this can be achieved also by the addition of staphylococcus vaccine to the blood 1 vitre. similarly an addition of tuberculin to the extravascular blood will increase the bactericidal power of the blood to staphylo- coccus, increasing at the same time the phagocytic efficiency of the icucocytes. these laboratory experiments are in consonance with the sta- tistical results obtained in connection with anti-pneumono- coccus inoculations at the premier mine in the transvaal. here, in ror2, in addition to astriking reduction in the incidence and death-rate of pneumonia, there was achieved a striking reduction in the incidence and death-rate from “‘ other diseases. ” derivation of product of immunisation the discussion of the deeper problems as to where anti-bacterial substances are elaborated in the body, and as to how their production is to be explained, may be deferred for a moment. tor the facts relat- ing to immunisation against bacterial toxins must first be taken into consideration, by bringing out the following points: (1) the machinery of immunisation is in reality.a machinery for neutralising or otherwise disposing of poisonous substances— poisonous substances being by definition those which enter into crippling or lethal chemical combination with the blood fluids and tissues. (2) the machinery of immunisation achieves its ends by furnishing substances which enter, as the case may be, into neutralising or precipitating or destructive union with the poisonous substances above spoken of. (3) the machinery of immunisation is brought into operation only by a particular class of poisons—to wit, by those which enter into crippling but not immediately lethal chemical combination with the cellular protoplasm—those which, to use the expressions of ehrlich, intrude themselves into the “ side-chains’ and not into the ‘vital ring”? of that protoplasm. of such poisons four kinds specially invite attention. these are: (a) the poisonous constituents of the bacterial protoplasm, (b) the albuminous substances contained in foreign sera and certain other foreign al- buminous substances, (c) bacterial toxins such as those which can be filtered off from cultures of diphtheria and tetanus and (d) vegetable and animal toxalbumens such as abrin, ricin and the various snake venoms. with respect to the first the body responds to their inoculation by a production of bactertoe-tro pic substances, i.c., substances which enter into detrimental or lethal chemical combination with bacteria. the inoculation of sera is followed by the elaboration and delivery into the blood of sero- tropic substances which neutralise and precipitate these sera. the inoculation of bacterial toxins in like manner—and this sovereign discovery was made by behring—leads to the pro- duction and delivery into the blood of toxitropic substances. these, known as bacterial anfiloxins, neutralise and precipitate the corresponding toxins. and, finally, the inoculation of toxal- bumens is followed by an elaboration and delivery into the blood of the appropriate neutralising substances. practical results —the discovery of bacterial antitoxins had led to important practical applications in connection with the treatment and prophylaxis of, in particular, diphtheria (see infectious fevers) and tetanus (g¢.v.) by virtue of the fact that toxins and antitoxins lend themselves to accurate quanti- tative study, it has contributed much to our knowledge of the machinery of immunisation. it was through the study of the curves of immunising response made to the inoculation of tetanus toxin that the negative phase first became known. immunity again it was by the study of antitoxin production that it was for the first time unequivocally established that the organism which has made previous response to even a minimal quantum of a toxin is thereafter capable of responding to any further quantum of that poison with a prompter and ampler elaboration of antitoxins. further, by the study of the antitoxin content of the blood in its relation to diphtheria toxin, it has been shown that the pres- ence of even a small quantum of antitoxin in the blood protects against infection, and further that the insusceptibility of the majority of adults to diphtheritic infection is correlated with the possession of a minute quantum of antitoxin derived, as it would seem, from repeated minimal diphtheritic infections contracted in their earlicr life. the same would appear to hold also of the scarlet fever streptococcus. we have here, as reflection will show, facts which illuminate the epidemiology of diphtheria and scar- latina and show that it is possible and may under circumstances be advisable to substitute for a prophylactic inoculation of a bacterial vaccine, an injection of antitoxin, or alternatively an injection of such quantum of toxin as will evoke an antitoxic response. two further points about antitoxins have important bearings upon the problem as to where and how products of immunisa- tion are produced in the organism. (1) antitoxins are quite rigidly specific—each antitoxin neutralising only the particular kind of toxin in response to which it was engendered. (2) after a first inoculation of toxins antitoxins are only very slowly produced. ordinarily an interval of 10 10 20 days elapses before they make their appearance in the blood. these properties are not, let it be noted, differential properties of antitoxins; they characterise also certain kinds of bucterio- tropic substances. specificity and comparatively tardy appear- ance in the blood characterise for example agglutinins, and the so-called “‘ thermostable immune bodies.” since there are two kinds of products of immunisation: one kind that are eminently non-specific and which are produced immediately (and can, as we have seen, be produced in the blood in vitro); and another kind which are rigidly specific and are elaborated only after a considerable lapse of time and are so far as appears produced only 1 vive; we may now seek for an answer to the problem as to how and where these various prod- ucts of immunisation are engendered. since it may be taken as certain that these two kinds cannot well originate in the same cells and be engendered by the same kind of metabolic operation, we may divide up the problem and consider first by what cells and by what kind of metabolic operation the non-specific anti- bacterial substances are produced and then take up the question as to where and how antitoxins and such antibacterial substances as are specific are generated. production of non-specific antibactertal substahces.—t he former question presents no difficulty. the facts set forth above make it clear that non-specific antibacterial substances are elaborated by the leucocytes. and further the facts suggest that the leuco- cytes produce these substances as ordinary secretion incited by the chemical products derived from bacterial and cellular disintegration products applied in suitable concentration. further the facts comport with the idea that leucocytes which have elaborated antibacterial secretions but have not as yet ex- creted these into the environing blood fluids will, by virtue of their increased content in antibacterial substances, possess in- creased antibacterial efficiency, while the blood fluids will not have gained anything in antibacterial power. conversely leucocytes that have excreted their antibacterial substances will exhibit diminished antibacterial power and the blood fluids which have received these secretions will have received an accretion of antibacterial power. production of specifie products of immunisation: fehrlich’s side-chain theory—the problem as to how these products of immunisation which indenture chemically with only one counter- part substance are engendered in the body, is of quite another order of difficulty, and it is one of the memorable achievements of ehrlich to have conceived how the furnishing of such specific 417 products of immunisation could be accounted for. the problem presented itself to ehrlich’s mind in the following vivid manner: “ tf,” it was thus that ehrlich communed with himself, ‘‘ if i take a guinea-pig—that is to say, a creature whose country of origin is southern america—and administer to it abrin—a poison derived exclusively from africa (and thus one which neither the tame guinea-pig nor its ancestry can ever have encountered) and if i now find that my guinea-pig furnishes me with an antidotal substance which indentures with the abrin as does a key with the wards of the lock for which it is made, is there then for me any way of escape from the conclusion that the organism of my guinea-pig has specially constructed an antidotal substance to fit the particular kind of poison i have administered—performing in this a feat of chemical analysis and synthesis which would balk the ablest chemist?’”? from the intellectual impasse into which this interrogatory seemed to conduct there was, ehrlich discerned, a possible way of escape. he reflected that there must of necessity exist in the organism of any animal which is affected by a given poison a counterpart substance(or to use his technical term) a receptor which enters into chemical combination with that poison. in other words there must exist already pre-. formed in the organism of susceptible animals, substances which have a chemical constitution such as would admit of their func- tioning as antitoxins. at the same time these counterpart substances differ funda- mentally from the non-specific antibacterial substances which were considered above. first of all they are not, as are the sub- stances last mentioned, available in the form of secretory prod- ucts produced only with a view to their being ejected from the cell. instead of that, specific counterpart substances are integral elements of the cellular protoplasm, and elements of which it may be assumed with certainty that they subserve special func- tions in the internal economy of the cells of which they are con- stituents. further the specific counterpart substances we are here considering differ from the non-specific antibacterial sub- stances in the respect that while these latter are elaborated only in one particular variety of cell (to wit, in the leucocyte) the for- mer are widely distributed in the organism, being located in each case in a clifferent assortment of cells. thus, for example, the counterpart substances to which the diphtheritic toxin would anchor itself would be located in a different assortment of cells than the counterpart substances with which the tetanus toxin would combine. and again the counterpart substances which would combine with abrin would be different. this would hold true also of the counterpart substances which would unite with the poisons derived from each particular variety of bacterial protoplasm. so far it has been shown only that susceptible animals must by the very nature of things contain in their cell-protoplasm con- stituent elements which are the exact chemical counterparts of poisons. we are still very far from the solution of the mystery (a) of the organism furnishing antitoxins in the circulating blood; (5) of its furnishing antitoxins only to special classes of poisons; and (c) of its furnishing these in quantities far in excess of the quantum of counterpart substances originally contained in the organism. ehrlich, in exploring for some way of exit from the labyrinth constituted by these questions oriented himself by the aid of a ground-plan, in which there was set out his general con- ception of the stereo-chemistry of protoplasm. in the plan in question the protoplasm is a structure made up of side- chains assembled round a central ring—the continued life of the protoplasm depending upon the integrity of the central (or as we may call it vita/) ring; while the side-chains con- sist of elements which are,integrated into the protoplasm for its nourishing and vital functioning. to this original ground plan there was now added by ehrlich a new feature. the con- ception which he now added was that the side-chains of the pro- toplasm would, as soon as they became redundant, be cast forth from the cell into the circulating blood, forming there what he called free receptors. interpreted in the light of this so-called side-chain theory, the incorporation of poisons which make a chemical attack upon the a418 vital ring of the cell protoplasm would abrogate the life of the cell and would therefore be incompatible with an elaboration of antitoxins. the situation is entirely different when the poison, instead of directing its attack to the vital ring, anchors itself on to one of the side-chains. after a temporary putting out of action of those functions which are discharged by the particular side-chains in question, this would lead to the replacement of the crippled side-chains, and thereafter toa hyper-replacement and to such redundancy of these in the proteplasm as would in- volve casting forth these side-chain receptors into the circulating blood. this theory, which is quite as applicable to the production of specific antibacterial substances as to the production of anti- toxins—wouldseem to lie open to critical assault in that the hyper- replacement of side-chains does not necessarily conduct to an excretion of these into the circulating blood. in point of fact in the case of muscle, on which ehrlich here relies, it leads to something very different, to a hypertrophy of this tissue. finally, the side-chain theory has met with hostile criticism more especially on the ground that it would compel us to believe that the noble tissues, such as those of the central nervous tissue which are poisoned by the toxins of diphtheria and tetanus, can be converted into secretory organs so prolific as to furnish in the blood tens and hundreds of thousands of units of the correspond- ing antitoxins. in point of fact the side-chain theory does not in any way require us to believe this. it would do so only if it had been established that poisons such as diphtheria and tetanus toxins attack only the central nervous system. but in point of fact ehrlich assumed that the poisons which are responded to by a production of antitoxins are all polyiropic—in other words they turn towards and combine chemically with a number of different tissues. so far therefore as the side-chain theory is concerned, we are thus authorised to assume that, not the cells of the central nervous system, but all or any of the other and less noble tissues which are affected by the toxins, are those which produce the harvest of antitoxins. see e. mechnikov, immunity in infective diseases, trans. by f. g. binnie (1907); sir a. e. wright, technique of the test and capillary glass tube (1921). (a. wr.) imperial preference.—this consists in the charging, by states belonging to the british empire, of lower import duties on goods coming from another state of the empire than on like goods coming from countries outside the empire, or in exempting empire goods from duty altogether. history of the movement—until after the middle of the roth century, colonial products enjoyed a preference in the customs tariff of great britain, and british goods in the tariffs of the colonies. preferences in both directions disappeared about the same time. but while great britain removed tariff restrictions equally from all imports, from whatever source, the colonies— now obtaining responsible government, and looking upon cus- toms as the only available source of public revenue—proceeded to impose equal duties on all imports, from whatever source. the british govt. in vain protested in 1859 against the imposi- tion of duties by canada on british goods. the govt. of canada insisted on ‘‘ the right of the people of canada to decide for themselves both as to the mode and extent to which taxation shall be imposed.” the principle of tarifi autonomy was hence- forward acquiesced in by the british govt. and acted upon by the self-governing colonies. this was the situation for almost 40 years, in the course of which colonial tariffs became distinctly heavier. so great, however, was the reliance in great britain on the most favoured nation clause in her commercial treaties with european countries, that by her treaty with belgium in 1862 and with the german zollverein in 1865 she actually bound her colonies, without consulting them, to grant as favourable treatment to the products of the treaty country as to those of the mother coun- try, i.e., to grant no preference to britain. changed sentiment.—a new stage in intra-imperial trade relations was opened in 1897. in that year canada granted tariff concessions to all countries treating her on equally favour- able terms. in effect this was a preference to british goods; and imperial preferench in 1898 the canadian tariff act was converted from one of general reciprocity to one avowedly of british preference. the imperial govt. had already in 1897 given notice to terminate the treaties with belgium and the zollverein. in 1902 the policy of canada became the policy of the domin- ions. at the colonial conference of that year in london the following resolution was passed:— that ... it is desirable that those colonies which have not al- ready adopted such a policy should, as far as their circumstances permit, give substantial preferential treatment to the products and manufactures of the united kingdom. that the prime min- isters of the colonies respectfully urge on h.m.’s govt. the ex- pediency of granting in the united kingdom preferential treat- ment to the products and manufactures of the colonies, either by exemption from or reduction of duties now or hereafter imposed. effect was given to this resolution by new zealand and south africa in 1903 and by australia in 1906. tariff reform—meanwhile in england the re-imposition for revenue purposes in 1902 of the old registration duty of 1 shilling a quarter on imported wheat had raised hopes of preference in canada which were defeated by the abolition of the duty next year. the episode completed the conversion of joseph cham- berlain to the principle of preference; and imperial preference was & prominent element in the policy of tariff reform which he laid before the country in 1903. the movement, however, failed at the time to receive sufficient popular support in great britain. at the next colonial conference in 1907, though the resolutions of 1902 were reaffirmed by the colonial representa- tives, the british govt. put in a definite reservation that they could not assent in so far as the resolutions implied that it was necessary or expedient that the fiscal system of the united king- dom should be altered. progress during the war.—the world war and the generous support which the dominions gave the mother country had considerable effect on public sentiment in great britain. early in 1917 the important committee appointed by the govt. to consider commercial policy after the war (presided over by lord balfour of burleigh) recommended:— that h.m’.s govt. should now declare their adherence to the principle that preference should be accorded to the products and manufactures of the british overseas dominions in respect of any customs duties now or hereafter to be imposed on imports into the united kingdom. a few weeks later the imperial war conference expressed itself in favour of ‘ the principle that each part of the empire, having due regard to the interests of our allies, shall give specially favourable treatment and facilities to the produce and manufac- tures of other parts of the empire’: a resolution now passed unanimously by the representatives no longer of the dominions alone but also of great britain. in april 1917 mr. lloyd george and mr, bonar law, on behalf of the coalition govt., announced their acceptance of the principle of preference, making it clear that this did not involve the taxation of food. in sept. 1918 the british govt. withdrew from the brussels sugar convention on the express ground that they had “ now approved the principle of giving preference to empire sugar.” and, finally, in the finance act, introduced by mr. austen chamberlain as chan- cellor of the exchequer in april ror9, preferential rebates on imports from the colonies or exemption from surtax were granted on practically all articles dutiable under the existing tariff, the range of dutiable articles had been increased under stress of war. for many years before 1915 the only duties imposed by britain were either purely for revenue purposes—those on tea, cocoa, coffee, sugar and tobacco; or for revenue with a certain mixture of ethical motive—those on wines and spirits. but the finance act of 1915 had introduced duties also on certain manufactured goods (the ‘‘ mckenna duties ’’)—cinema films, clocks and watches, motor-cars and musical instruments. these were intended as luxury taxes, but had some protective effect. on these the measure of 1919 was now able to give preference. post-war changes —the area of preference was still further enlarged by the safeguarding of industries act in 1921. part i. of this act provided for the imposition of duties on certain impressionism—income tax articles produced by “ key industries.”” the list included cameras and optical lenses and a large number of scientific instruments and apparatus, chemicals and special appliances, deemed essen- tial for the safety of the empire; and from these duties empire goods were entirely exempted. the growth of manufactures in canada had affected the sit- uation by enlarging the possibility of advantageous preference in great britain beyond the primary foodstuffs: motor-cars are an example. a similar extension of possibilities from australia was brought about by the growth of fruit farming, largely as the result of the settlement on the land of ex-soldiers. the british govt. took the opportunity of the imperial conference of 1923 to announce its readiness to enlarge the existing pref- erence on dried fruits, to increase the rebate on empire tobacco and on certain wines, and to take other action of a similar char- acter. before these promises could be fulfilled, the baldwin govt. fell from power. the macdonald ministry which followed declined to carry out the intentions of its predecessors; abolished the mckenna duties; and, though it did not entirely throw over preference in revenue duties, so reduced the tax on sugar, tea and dried fruits as to make the preference of less value. preferences granted by britain.—on the return to office of mr. baldwin at the end of 1924, the mckenna duties were restored with the accompanying preferences; and the preference on dried fruits, tobacco, wines and sugar was increased. the range of preference was further widened in two directions. the new safeguarding of industries (customs duties) act, r925, imposed duties on imported cutlery, gloves and incandescent mantles; while the budget of that year introduced duties on silk, natural and artificial. to each of these new duties, empire preference was attached. since the first grant of preference to the mother country by the great dominions, changes have from time to time taken place both in the general rates of duty and in the extent of the preference. in 1923 canada, having in mind the removal of certain restrictions on the importation of cattle into the british market, undertook to give a discount of 10% on existing duties on british goods coming through canadian ports. australia increased its preference to british goods in 1920, and gave assis- tance to british trade both by anti-dumping legislation and by measures with respect to dyes, and during the last two decades a whole complex of preferences has grown-up between the several dominions and colonies, many of them the result of definite treaties, and thus preference within the british commonwealth of nations has already become a considerable factor in the eco- nomic and political world situation. (see also tariffs.) bibliography.—the least partisan and most complete history of the whole movement down to 1921 will be found in a report on colonial tariff policies (1922), prepared for the u.s. tariff com- mission. much information as to the views of the dominions and as to the volume of trade affected is given in the record of proceedings of the imperial economic conference of 1923 (cmd. 2009, 1924). the nature and extent of the preferences accorded to great britain, down to march 1925, together with the conditions governing the concessions, will be found in the survey of overseas markets (1925) by the committee on industry and trade appointed by the british govt. in 1924. that committee reported that ‘‘ while it is difficult to obtain any exact statistical measure of the benefit to british trade of the preferential treatment, the surveys of british dominion markets and the statistics of distribution of british trade leave no room for doubt that the advantage has been substantial.’’ (wo. a.) impressionism: see painting. inchcape, james lyle mackay, 1st viscount (1852- ), british shipowner, was born at arbroath, forfarshire, sept. 11 1852, and educated there and at elgin. in 1874 he went to india to join the firm of messrs. mackinnon, mackenzie & company, calcutta, of which he ultimately became senior partner; he became a member of the legislative council of the viceroy in 1891 and a member of the council of india in 1897. he was created k.c.i.e. in 1894. in 1902, consequent upon the boxer rebellion, sir james mackay negotiated a commercial treaty with china (see 6.204); he was then created g.c.m.g. in 1911 he was raised to the peerage as baron inchcape of strath- naver. before the world war broke out, lord inchcape was 419 already one of the most prominent figures in the british business world. as a representative of the shipping industry he took a leading part in all its affairs both during the world war and after. he served on most of the government commissions of inquiry both in india and england. he was a member of the geddes committee on national expenditure (1921), and chair- man of the indian retrenchment committee (1922). in 1924 he was created viscount and g.c.s.i. the positions of chairman of the p. and o. steam navigation company and director of the national provincial bank and suez canal company made him a leading figure in business circles.