80 ILLINOIS ACADEMY OF SCIENCE. 



directly exposed. As the action is to a degree selective, radium 

 and X-rays have had very valuable practical uses in these diseases. 



(5) Finally the anodyne effect of radium has had some appli- 

 cation in the relief of itching and of pain. 



The therapeutic uses of radium are obtained from the above 

 indications. The indications which 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 Httle to the facts 

 given above. Experiments on rabbits have shown that exposure 

 to the radiations cause anaesthesia in peripheral nerves (Beck), 

 confirming a fact established by clinical experience. Danysz and 

 Bohn have shown that the nervous system of certain young ani- 

 mals is peculiarly sensitive to the effects of radium, exposures so 

 arranged as to reach strongly the cerebrospinal axis causing pare- 

 sis, ataxia, convulsions and death. These phenomena, with nega- 

 tive controls, were elicited in mice, which proved most sensitive, 

 and in guinea pigs, and in rabbits. The sensibility is very much 

 greater in the very young animals, persists in older mice, but dis- 

 appears in great degree in adult guinea pigs and rabbits. Similar 

 effects upon the nervous system of man either from radium, or 

 X-rays do not occur from their external applications. 



I cannot 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 subjects has been 

 carefully summarized in a paper by Hussakof of Columbia Uni- 

 versity which is readily available. 



Several experiments have shown the inhibitive or, under 

 stronger exposures, destructive effect of radium rays upon vari- 

 ous bacteria in cultures — the bacillus prodigiosus, colon bacillus, 

 typhoid bacillus, anthrax bacillus 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 effects of 

 the Alpha and Beta rays because of their very slight penetration 

 as compared with the softest X-rays. They indicate a close sim- 

 ilarity, with a difference chiefly in degree, in their biological ef- 

 fects between Alpha and soft Beta rays and ultra Violet rays. 

 Similar results have been obtained by several observers from ex- 

 posures of numerous forms of protozoa. Their growth is at first 

 stimulated, then inhibited, and after intense exposures they are 



