1004 



SCIENCE 



[N. S. Vol. XXXIII. No. 861 



lesions as can be directly exposed. As the ac- 

 tion is to a degree selective, radium and X- 

 rays have had very valuable practical uses in 

 these diseases. (5) Finally the anodyne ef- 

 fect of radium has had some application in 

 the relief of itching and of pain. 



The therapeutic uses of radium are ob- 

 tained from the above indications. The indi- 

 cations vphich might seem to be derived from 

 the effect upon other organisms, especially 

 upon bacteria, yet to be considered, have not 

 increased the practical application of the 

 agent. 



Experiments upon other mammals have 

 added little to the facts given above. Ex- 

 periments on rabbits have shown that ex- 

 posure to the radiations causes anesthesia in 

 peripheral nerves (Beck), confirming a fact 

 established by clinical experience. Danysz 

 and Bohn have shovsoi that the nervous sys- 

 tem of certain young animals is peculiarly 

 sensitive to the effects of radium, exposures 

 so arranged as to reach strongly the cerebro- 

 spinal axis causing paresis, ataxia, convul- 

 sions and death. These phenomena, with 

 negative controls, were elicited in mice, 

 which proved most sensitive, and in guinea 

 pigs and rabbits. The sensibility is very 

 much greater in the very young animals, 

 persists in older mice, but disappears in 

 great degree in adult guinea pigs and rabbits. 

 Similar effects upon the nervous system of 

 man from either radium or X-rays do not 

 occur. 



I can not take more than enough time to 

 refer very briefly to the effects of radium 

 upon micro-organisms, upon development and 

 upon plants. The knowledge upon these sub- 

 jects has been carefully summarized in a 

 paper by Hussakof, of Columbia University, 

 which is readily available. 



Several experiments have shown the inhib- 

 itive or, under stronger exposures, destruc- 

 tive, efieet of radium rays upon various bac- 

 teria in cultures — the bacillus prodigiosus, 

 colon bacillus, typhoid bacillus, anthrax ba- 

 cillus and the spirillum of cholera. These 

 are the only biological findings differing from 

 those with X-rays, and are probably due to 



the greater superficial effect of the alpha and 

 beta rays because of their very slight pene- 

 tration as compared with the softest X-rays. 

 They indicate a close similarity, with a dif- 

 ference chiefly in degree, in their biological 

 effects between alpha and soft beta rays and 

 ultra-violet rays. 



Similar results have been obtained by sev- 

 eral observers from exposures of numerous 

 forms of protozoa. Their growth is at first 

 stimulated, then inhibited, and after intense 

 exposures they are destroyed. 



Experiments on various eggs, embryos and 

 larvse have shovsru, as would be expected, in 

 these embryonic tissues, a high degree of 

 susceptibility. Grovrth is retarded, monstros- 

 ities develop, and, from prolonged exposure, 

 death occurs. 



In plants the results of experiments may 

 be summarized briefly as first stimulation of 

 growth, and under stronger application, re- 

 tardation or complete inhibition of growth. 



This consideration has been directed to the 

 effects of radium rays. As to the emana- 

 tions, it may be stated briefly that experi- 

 ments with the emanations upon young mice, 

 upon bacteria, and upon protozoa show re- 

 sults quite like those from exposure to the 

 rays. 



There is apparently no difference in kind 

 in the effects upon tissues between the differ- 

 ent radium rays. Alpha rays have so little 

 penetration that their effect is expended en- 

 tirely upon the most superficial tissues, but 

 when they are screened out the only differ- 

 ence in the reaction is one of intensity and 

 depth. Exner, in a repeated experiment, by 

 deflecting the beta rays with an electro-mag- 

 net directed them upon one white mouse 

 while the gamma rays fell upon another mouse 

 equidistant from the radium. Fifteen days 

 after exposure, which had been for 18% 

 hours, a similar ulceration appeared on the 

 tails — the exposed areas — in both mice. All 

 three forms of radium rays then, are physi- 

 ologically active. This fact might fairly be 

 inferred from their actinic properties. For 

 the physiological effects of aU forms of 

 radiant energy, there seems every reason to . 



