RADIOTHERAPY AND RONTGENOLOGY

the discovery of x-rays by rentgen in the autumn of 1895 marked an advance in the history of science, which, even yet, is not appreciated by the average individual. roentgen himself realised immediately the value of his discovery to the science of medicine, and communicated it to the physico-medical society of wurz- burg. since then, if one excepts the years of the world war, hardly a month has passed without some innovation. in 1910 the x-ray tube had varied but little from the original tube used by r6ntgen and crookes, the improvements in focus- ing and increasing the intensity of the rays being due to the labours of campbell swinton and chiefly to prof. jackson in 1896; indeed the modern focus tube (gas tube) has not materially changed since then. in this tube, the current is carried across the tube by a certain amount of gas, which is left behind in the pro- cess of evacuation. the current, impinging on a tungsten target, under a pressure of anything over 80.000 volts, results in the production of x-rays, which rays are now known to be electro- magnetic impulses of very short wave-length. the only dis- advantage of this tube is that individual control of the current and voltage is not absolute owing to fluctuations in the amount of residual gas. despite this, however, it is largely used and for many purposes possesses advantages over the coolidge tube. the coolidge tube.—at a later period dr. coolidge of new york discovered that a glowing body emitted electrons, and at once designed a new type of bulb in which the current was car- ried across the vacuum by a stream of electrons from a hot tung- sten wire. the hotter the wire the greater the current which 284 passed across the bulb. this, of course, solved the problem of separate control of the voltage and the current and thereby the problem of being able to reproduce exact working conditions at any interval. unfortunately the hope, raised at first by the pro- duction of this tube, of obtaining an absolutely homogeneous beam of x-rays, was not realised. production of rays.—the intensity of the x-rays depends upon the voltage employed to produce it and as the manu- facture of high-potential generators (induction coils and step-up transformers) has improved out of all recognition since 1gto, we can now produce rays of very great intensity, far greater indeed than are needed for racliographic purposes. on the photographic side, improvements in technique have been very noticeable, the most noteworthy improvements being the use of intensifying screens to shorten exposures, double- coated films to increase the contrast of the negative and the potter-bucky diaphragm, the latter an ingenious contrivance for the purpose of cutting out secondary radiations and thereby sharpening the resulting picture. use in war therapy.—during the years 1914-8 science was more or less subservient to the claims and the necessities of war- fare, but even in this limited field x-rays were of enormous help. the localisation of bullets and shrapnel, which by any other means would have been impracticable, if not impossible, was carried out by numbers of experts, and to the untiring energies of these men a host of soldiers practically owe their lives. use in diagnosis —the past few years have been ones of very great activity in the x-ray world. improvements in technique previously mentioned have brought the use of x-rays into much greater prominence in the study and the diagnosis of internal diseases (see diagnosis). sciagrams of the lungs, which were difficult to make and still more difficult to interpret, are now of the very greatest possible value in the study of diseases of the heart (q.v.) and lungs. it is no exaggeration to say that no diagnosis of disease of either of these organs is complete without an x-ray examination. this advance is seen in the large hospitals for diseases of the chest, where formerly only a few hundred examinations were made, now the number amounts to thousands in the year. whereas the air-filled lungs showed up clearly against the more dense, blood-filled heart and solid thoracic walls, the abdominal organs, that is to say the hollow viscera, being all of the same density, were all penetrated equally by x-rays and consequently were not readily differentiated on a plate. for a long time this difficulty appeared to be unsurmountable. many substances were known to be opaque to x-rays but none of them could be taken with safety. haudek, of vienna, made careful experi- ments with bismuth sulphate mixed with jam and watched its progress through the oesophagus, but completely forgot to look for it in the stomach. use of besmuth.—in 1901 becker gave small doses of the same material and was the first to publish anything definite about the radiology of the alimentary tract. his results were confirmed in the same year by other workers, but the danger of poisoning {chiefly from metallic impurities in the bismuth) was so great that not sufficient could be given for diagnostic purposes, and nothing of any special value resulted. somewhat later, the publication of a paper on the treatment of gastric catarrh by large doses of bismuth inspired rieder, of munich, to give large doses of bismuth in order to examine the stomach and intestines by means of x-rays. some few cases of poisoning were later reported, but with the help of the chemist an absolutely non-toxic preparation of bismuth carbonate came into use. the production of this non- toxic preparation of bismuth was difficult and it never attained to universal popularity. in ro1o experiments were made with barium sulphate—which was found to be almost as opaque as bismuth and not only much more readily freed from inorganic impurities but infinitely cheaper to use. with very few excep- tions radiologists use some form of this salt in diagnoses. the gastro-intestinal tract—the production of a safe and suitable method of making the gastro-intestinal tract opaque radiotherapy and rontgenology very greatly stimulated the investigations which were being carried on as to the condition of the alimentary tract in health and in disease. the study of both is still far from complete but, even with the results so far attained, diagnosis of intra-abdominal conditions has been greatly improved and numerous complaints previously described as ‘ indigestion”? and “ gastritis,’ for example, are now readily classified. cancer and gastric ulcers —cancer of the stomach gave fairly typical x-ray evidence, but gastric ulcer proved almost as elusive to the radiologist as to the clinician. certain investigators had observed a “ niche ” or recess on the wall of the stomach but its significance was not appreciated. in the same year (1910), haudek and others, but chiefly the former, produced definite evidence that the “ niche ” was in reality an ulcer on the gastric wall filled with barium. since then many other signs indicative of gastric ulcer have been noted and now the diagnosis of this condition is not a difhcult matter. ulceration of the duodenum, thanks to the labours of carman and miller in particular, and to gregory cole and barclay, this region of the intestinal tract is becoming an open book to the radiologist. apart altogether from the value of x-rays in the investigation of disease, many new facts of physiological and anatomical (see anatomy) interest have been elucidated. actual kinemato- graph films of the movements of the stomach and intestines during the process of digestion have lately been exhibited at a congress held in london, and on the continent the writer has seen films of the heart and lungs showing their movements. by in- jecting the blood-vessels after death with a salt of lead in sus- pension, much valuable information to anatomists in the study of the vascular system has been secured by means of sciagrams. therapeutic values.—from the earliest days of the discovery of x-rays, they were known to have certain curative properties, and scientists all over the world have been experimenting to place this form of treatment on a sound and scientific basis. intract- able skin diseases (q.v.) which resisted every other remedy often responded to x-rays, and it was noticed that some forms of malignant disease disappeared after treatment by irradiation. means of accurately measuring the dosage of the rays were not known, but cancer had become so terrible a scourge that they were utilised indiscriminately for its relief, and at times with disastrous results. from 1905 onwards methods of measurement improved and in 1914 a dose could be administered with a certain amount of accuracy, the risk of burning became almost negligible, and we are now in possession of instruments capable of giving precise knowledge as to the amount of x-rays falling upon a given area. a spectroscope is used which takes a photograph of the x-ray spectrum. from it the wave-length can be ascertained and, the wave-length and the intensity of an x-ray beam being synonymous terms, it follows that the shorter the wave-length the more intense the x-ray. most of this work was carried on in germany, where the idea prevailed that it was only necessary to get an intense enough ray and to measure it carefully in order to kill cancer. apparatus for the production of these very intense rays was soon devised and before very long a great number of patients were undergoing treatment, so rapidly did this idea stimulate the popular imagina- tion. in the early stages of this new form of x-ray therapy the results appeared to be most encouraging and the conquest of cancer was thought to be within reach. subsequent statistics showed relief to be merely temporary. great credit is, however, due to the early german workers and to our own specialists in britain for the ingenuity and skill shown in standardising and rendering accurate the dosage of x-rays; but as a method of treatment of cancer we are getting no better results than were obtained in 1910. russ and colwell (in an illuminating book, radium, x-rays and the living cell) put the matter thus: “in radiology applied to biological problems there is a double difficulty, for the intensity of the radiation used, whether it be x-rays or radium is a quantity which under many experimental conditions presents very considerable difficulties in its accuracy of measurement, and the animal itself provides a complex oe refuses to be reduced to simple terms.’ radium bintrogrrapphy.—h. a. colwell and s. russ, radium, n-ravs and the living cell (1924); rk. knox, radtography and radito-thera- deutics (1919). (s. me.) radium (see 22.807d) is an element of atomic weight 226, the highest term in the alkaline earth series, calcium, strontium, barium. it is a metal having many analogies with barium and it is also a “ radioactive substance”’, 7.¢., a substance that suffers a spontaneous disintegration accompanied by the emission of radiation (see raproactivity). this radioactive property con- fers on radium a special importance for scientific purposes or for medical use, and is also the cause of the extreme rarity of the element. though radium is only one of numerous radioactive substances, being neither the most radioactive nor the most abundant, its rate of decay and the nature of the products of its disintegration have proved particularly favourable in the appli- cations of radioactivity, and make it the most important of radioelements. chemical properties spectrum.—if£ we do not consider the chemical actions of the radiations it emits, radium has exactly the properties that can be expected from its place in chemical classification. radium is placed by its atomic weight 226, in the second column of the mendelycev table. with an atomic number 88, it is the last term of the alkaline earth series. the salts of radium are colourless and nearly all soluble in water; the sulphate and carbonate are insoluble. radium chloride is insoluble in concentrated hydro- chloric acid and in alcohol. radium and barium salts are iso- morphous. preparation of radium.—metallic radium has been prepared in the same way as metallic barium, by electrolysis of a radium salt with a mercury cathode, mercury being eliminated by heat- ing the amalgam in dry hydrogen, the metal is white and melts at about 7oo°. it attacks water and is rapidly altered by the contact of air. the atomic weight can be determined by the methods used for barium, e. g., by weighing the anhydrous radium chloride and the equivalent silver chloride or bromide. optical spectrum.—the optical spectrum is composed, as with the other alkaline earth metals, of a relatively small number of lines of great intensity; the strongest line in the limit of the violet spectrum is 3814-6a, and this line is a very sensitive test for the presence of radium; but spectral analysis is little used in the detection of radioelements, the radioactive properties ofiering a considerably higher degree of sensitivity. the high frequency spectrum is in accordance with the prediction for the element of atomic number 88. radioactive properties radioactive elements in general.—the theory of radioactive transformation has been established by rutherford and soddy (see raproactivity). if # is the number of atoms of a radio- element, the proportion of the atoms destroyed in a certain time tis always the same, whatever » may be; the number of atoms decreases with the time ¢ according to an exponential law, n= noe where nis the raclioactive constant of the substance. the reciprocal of is called the ‘average life’ of the element; the time t necessary for the transformation of the half of the atoms is called the “‘ period’ and related to the constant a by the expression t = loge2/x. radioactive substances emit three kinds of rays known as a-, b-and-+y-rays. the a-rays are helium nuclei carrying each a posi- tive charge equal to double that of the elementary charge; they are expelled from the nuclei of the radioactive atoms with a great velocity (about 1-5 x10% to 2-3 x 10% cm./sec.). the 8-rays are electrons of various velocities which may approach the veloc- ity of light. the y-rays constitute an electromagnetic radiation of the same kind as light or x-rays, but their wave-length is generally much smaller and may be as short as o-ora. while the emission of some radioelements consists almost entirely of a-rays whose penetrating power is very small, other raclioele- ments emit §- and y-rays which are able to penetrate a consid- erable thickness of matter. 285 uranium-radium family——radium is a member of the uranium family, z.e., one of the elements resulting from the trans- formation of the uranium atom; its period is about 1,700 years. we give here the list of the radioactive elements of the uranium- radium family, the mode of their disintegration (a- or b-rays), the atomic number and the period. : _ _ atomic! | element and its num- period | disintegration ine (uranium) “a ; . : : 92 4:6 x10° years a a go 24°5 days uno ql i-t4 min. bi utt g2 1-2 xr0*8 years a | (onium) ‘a go 7*4 x101 years a (radium) ra . 88 1-7 x10 years a (radon) a : 86 3-82 days a raa 84 3-0 min. a rab 82 26-8 min. b | | rac 83 19°5 min. | b| | ra 84 106 sec. | a | | rad 82 16 years | bl | ik ‘ e , ; 83 4°85 days b : (polonium) po . , 84 139°5 days | a (lead) rag | the atoms of each element are formed out of the destroyed atoms of the preceding element. none of these atoms can exist in nature otherwise than in uranium minerals, unless recently transferred from such minerals by a chemical or physical process. when separated from the uranium mineral they must disappear, their destruction not being compensated by their production. only uranium and thorium are radioclements of so long a life that they have been able to last through geological times without any known production. according to the laws of radioactive transformation, in verv old minerals a state of equilibrium is attained where the ratio of the number of the atoms of the different substances is equal to the ratio of their average life. the ratio radium/uranium is about 3:-40x10 7 in the older minerals; accordingly we cannot expect to find a mineral containing a high proportion of radium. yet pure radium can be prepared in ponderable quantities while the other radioelements, except the slowly disintegrating ura- nium and thorium, are not capable of preparation in quantity, most of them because they exist in much smaller quantities. the quicker the disintegration of a radioactive substance, the smaller is its proportion among the earth’s minerals, but the greater its activity. thus radium is several millions of times more active than uranium and 5,000 times less than polonium. radiation of a radium tube-—small quantities of radium are frequently kept in sealed glass tubes called “ radium tubes.” radium emits only a rays and a feeble b-radiation; the pene- trating radiation emitted by a radium tube comes from the dis- integration products gradually accumulated by the radioactive transformations of radium; first, radon or radium emanation, a radioactive gas, the next term to xenon in the series of inert gases; secondly, radium a, b, c, called “ active deposit of rapid change ”’; thirdly, radium d, e and radium f or polonium, called ‘active deposit of slow change ”’; finally, inactive lead, and also helium generated in the form of a-rays. the strong penetrating radiation of a radium tube is emitted by radium b and c. when pure radium salt is sealed in a tube, the activity increases during about a month, till a state of equi- librium is attained between radium, radon and the active deposit 286 of rapid change, when the production of each of these elements is compensed by their destruction. the penetrating radiation con- sists in b-rays and in y-rays, the latter particularly known by its valuable use in therapy. the quantity of radon inequilibrium with one gramme of radium is called the “ curie.”’ if the radon is extracted and sealed sep- arately in a tube, radium a, b, c, will accumulate and the pene- trating radiation for one curie of radon will be the same as for one gramme of radium. but the activity of the radon tube decreases to half its value in 3-82 days, the period of radon, while the ac- tivity of a radium tube remains practically constant after equl- librium has been attained; the decrease is only 0-4°% in 10 years. effects of radiation —radiation of radium produces all the ordinary effects of rays (see radioactivity); lonisation of the gases, continuous production of heat, excitation of the phosphor- escence of certain substances (zinc sulphide, ctc.), colouration of glass, chemical actions (decomposition of water for instance), photographic actions, biologic actions. radium compounds ob- served in the dark exhibit a spontaneous luminosity, which is particularly bright in freshly prepared chloride or bromide, and is determined by the action on the salt of its own radiation. activity of radium.—the a-rays belonging to radium itself have a range of 3-4.cm. in air at 15° c.and normal pressure. the number of a particles emitted by radium was measured by dif- ferent methods of numeration (scintillations or counting cham- ber); the result varies from 3-40x 10! to 3-72 x 10!° particles per sec. and per gram of radium; from this data the average life of radium can be deduced. three other groups of a rays, of ranges 4-1 cm., 4:7 cm. and 7 cm. are emitted by radon and the active deposit, radium a, b, c. the heat produced by radium itself is about 25 calories per hour and per gramme. fora tube of radium in equilibrium with the disintegration products of rapid change, the production of heat is about 137 calories per hour and per gramme. this heating effect is principally due to the absorption of the energy of the a-rays. discovery of radium in the year 1896 h. becquerel discovered that uranium emits spontaneously a radiation that produces an impression on a photographic plate through a sheet of black paper, and ionises the air. mme. p. curie proved that this property, later called radioactivity, is characteristic of the atom of uranium and is possessed also by thorium. but she found that uranium minerals were much more active than could be predicted from their ura- niumcontent. by the hypothesis of the existence of a very radio- active unknown substance present in very small quantity, she undertook, with pierre curie, research for this substance in the uranium mineral called piichblende. the method they used in that work was entirely new; the result of the separations made by the ordinary process of chemical analysis was controlled by tests of the activity of every fraction; the activity was measured quantitatively by the current pro- duced by the substance when placed in a special ‘ ionisation chamber.”’ thus concentration of the radioactive property was traced in two fractions of the treatment, the fraction containing bismuth and the fraction containing barium. in july 1898, p. curie and mme. curie published the discovery of polonium, the element accompanying bismuth; in dec. 1808, yp. curie, mme. curie and g. bemont published the discovery of radium. though the existence of these new substances was certain, they were present only in a very small proportion in the products obtained at that time; yet demarcay was able to detect in the barium-radium mixture three new lines belonging to radium. only in 1902 did mme. curie succeed in preparing the first decigram of pure radium salt and made a determination of its atomic weight. the separation of barium was made by a process of fractional crystallisation. the work proved exceedingly diffi- cult in practice on account of the great quantities of material that had to be treated. later mme. curie made a new deter- mination of its atomic weight and prepared metallic radium. the new method used by p. curie and mme. curie for the radium discovery of polonium and radium—chemical analysis controlled by measurements of radioactivity—has become fundamental for the chemistry of radioelements; it has served since for the dis- covery of many other radioactive substances. the discovery of radium and the preparation of the pure element has had very great importance in laying the basis of the new science of radio- activity. the identification of its spectrum and the determination of its atomic weight have been decisive facts for convincing chemists of the reality of the new elements. industrial production of radium radium has been manufactured in several countries. the first factory was started in france in 1904, not six years after the discovery of radium. | afinerals.—radium is to be found in all uranium ores; however only those that have been mined in sufficient quantity for the extraction will be here mentioned. pitchblende or uraninite —uranium oxide more or less impure. mines in bohemia and belgian congo. autunite.—double phosphate of uranyle (uo2) and calcium. mines in portugal, united states and elsewhere. carnotite-—vanadate of uranyle and potassium. mines in colorado, australia and elsewhere. betafite.—niobo-titanate of uranium and calcium, with rare earths. mines in madagascar. the first radium was prepared from pitchblende from bo- hemia. later the principal exploitation was that of carnotite in colorado and of autunite in portugal. at the present time the most important supply is extracted in belgium from the pitch- blende of belgian congo. a mineral containing more than one decigram of radium per ton is considered as very rich. minerals were treated down to a few milligrams per ton. industrial treatment.—the method of industrial extraction of radium, in its essential points, is still the original method that was used and described by mme. p. curie. the operation can be divided in three parts: dissolution of the mineral, purification of a barium-radium salt, separation of radium from barium by fractional crystallisation, the treatment for dissolving the mineral differs from one mineral to another. autunite and certain carnotites are soluble in hydrochloric acid, but nearly all other minerals must be at- tacked by more energetic agents, for instance with the aid of sodium carbonate. when the mineral does not contain much barium, a certain quantity of barium salt is added in order to carry away the radium. the barium-radium mixture is separated. with some variations in the mode of separation of uranium and lead (always present in the mineral) or eventually vanadium, niobium, etc., the operation consists in separating barium-radium by precipi- tation as sulphates and redissolving these sulphates by ebulli- tion with sodium carbonate followed by a hydrochloric attack. generally the radium-barium mixtures pass more than once through the state of sulphates. after the purification of the barium-radium chloride, radium is concentrated by a process of fractional crystallisation, radium chloride, less soluble than barium chloride, being concentrated in the crystals. after this first enrichment the active salt is again purified particularly by the elimination of a residue of lead, and is transformed into bromide for the continuation of fractional crystallisation (the use of bromide was suggested by giesel). the final crystallisations are made on small quantities of salt in very acid solutions. all the operations are controlled by the ionisation method, to avoid the loss of radium. at the end of the purification, great care must be taken to protect the chemist from the action of the radiations, especially at the mo- ment of the filling of the tubes or apparatus with the radium salt. the radon liberated in the room during the fractionation must be eliminated by a constant aeration. | amesothorium.—some minerals of uranium contain also tho- rium. in these minerals radium is mixed with another raclio- element, mesothorium i, isotope of radium. mesothorium i is much more active than radium, but has less commercial value raemaekers—railways for the same activity, because its life is much shorter (6-7 years). mesothorium can be used instead of radium in certain cases. measurements measurement of the quantities of radium is very important for scientific as well as for commercial purposes. the quantities to be measured vary greatly. for instance, the tubes of radium prepared for medical use contain in general from 1 to 100 milli- grammes, but radium has often to be dosed in natural waters or minerals, where the quantities are of the order of 107 gr. and even down to 10! gr. per litre of water or per gram of mineral. for very small quantities, only an ionisation method of meas- urement can prove successful. for relatively great quantities, radium could be weighed but it would require a careful purifica- tion of the radium salt and the precision would in general be very unsatisfactory, considering the high price (about fro the milli- gramme of this element). here also, therefore, ionisation meas- urements are used for the sake of accuracy. for quantities ranging from about one-tenth of a mg. to the greatest quantities available the radium must be sealed in a tube where radon and the active deposit accumulate. measure- ments are made by comparing the ionisation produced in an ionisation chamber by the penctrating rays from the tube contain- ing the unknown amount of radium and from a standard tube placed in the same conditions. a correction is made for differ- ences of form or of absorbing power of the two containers. the sale of radium is made according to the certificates deliv- ered by national technical laboratories: national physical lab- oratory (london), radium institute (paris), radium institute (vienna), physikalische-technische reichsanstalt (berlin), u.s. bureau of standards (washington). discrimination between ra- dium and mesothorium i in sealed tubes is rather difficult. for this purpose, of commercial interest, scientific methods have been devised, based on the different penetrating power of the y- rays, or on the different production of heat. an international radium standard was prepared in ro1t by mme. p. curie. a quantity (about 22 milligrammes) of very pure radium chloride was exactly weighed and sealed into a thin tube of glass. this standard is kept at the international bureau at sevres, and secondary standards, carefully compared with this one, have been prepared for different countries. determination of the very small quantities of radium con- tained in a few grams of a mineral, or a few litres of mineral water, is made by measuring the quantity of radon it produces in a definite amount of time. the mineral is dissolved and radoh removed by passing a slow current of air through the solution, then after a few days, the radon accumulated in the solution contained in a close vessel is conveyed to a special lonisation chamber, where the current produced by the a-rays of radon and radium a, b, c, is measured. this allows calculation of the amount of radium in the solution, if the ionisation chamber has been standardised by a similar operation made with a known quantity of radium. for the standardisation a very dilute solu- tion 1s prepared by taking a small definite fraction of a solution containing a quantity of radium directly measurable by the penetrating rays. to facilitate the standardisation of apparatus, technical laboratories deliver standardised solutions or samples of radium-barium salt containing a known proportion of radium. the method of quantitative determination is exceedingly sensi- tive and can be used for amounts of radium from 10° gr. to 10° grammes. applications of radium the principal application of radium is the use for therapeutic purposes of the biological action of the rays (see radiotherapy; therapeutics). the biological action is a selective destruction of certain cells and can have very dangerous consequences, but can also be directed against nocive tissue, as for instance in the case of cancer. for medical use radium is put into tubes of glass or in platinum needles, sometimes also on flat surfaces recovered by a varnish, for the irradiation of the skin. another form of use is to keep radium in solution and to extract from 287 time to time the accumulated radon which, introduced into small tubes, has the same efliciency as radium till its activity has disappeared. the use of radium for pharmaceutical prepa- rations has been frequently tried. the scientific basis, however, in this case is far from being well established. experimentation on the improvement of the soil by small quantities of radium has been till now very limited and some favourable results in this direction have been claimed. — | by incorporating radium with phosphorescent zine sulphide it is possible to obtain luminous paints giving a weak light visible in darkness. the most important use of this paint is for watches. the quantity necessary is of the order of one-tenth of a milli- gramme per gramme of zinc sulphide. after sevcral years, the phosphorescent product is altered by the action of the rays and becomes less luminous, though the quantity of radium has not changed appreciably, | radium in nature-—radium exists in minute proportion in every kind of soil and water; the extraordinary sensitiveness of the methods of analysis has made it possible to ascertain this fact. 1f some inactive element is present in the same proportions, we are not able to detect it. the quantity of radium contained in the ordinary soil is of the order of 10°" or ro" gr. of radium per gramme while a good radioactive ore contains about 107? gr. of radium per gramme of mincral. radium existing in the depths of the earth is sometimes dis- solved by water and affects springs. other springs dissolve principally the radon liberated by the radium and their activity dies out with the radon. this would explain why certain mineral waters are reputed to be efficient for curative effect only when used directly at the source. some radio-active waters contain amounts of radium up to ro? gr. per litre the amount of radon can attain 10° curies per litre. the radium in the soil is the origin of the small quantity of radon present in the air and is partly responsible for the natural ionisation of the air which is known to be an important factor in the meteorological conditions of the atmosphere. radium and radioactive elements in general have played an important part in the evolution of terrestrial heat. it is not improbable that the radium present at the surface of the earth in a very dilute state has some connection with the evolution of life on our planet (see mme. curie, truiie de radioactivite, 2 vol. (1910). (am. cs i, cy) raemaekers, louis (1869- }, dutch cartoonist, was born at roermond, holland, april 6 1869. he was educated in amsterdam and brussels, and began his career by painting land- scapes, portraits and posters. in ro08 he produced his first political cartoons, and subsequently gained international fame by his violent anti-german cartoons in the amsterdam /7'el- egraaf and other papers during and after the world war.