THE 



AMERICAN NATURALIST 



Vol. XLII December, 1908 No. 504 



SOME PHYSIOLOGICAL EFFECTS OF RADIUM 

 RAYS 1 



PROFESSOR CHARLES STUART GAGER 

 New York Botakical Garden 



It is probable that no scientific discovery, since the 

 publication of Darwin's "Origin," has so revolutionized 

 our conceptions of natural phenomena as has the discov- 

 ery of radioactivity by Henri Becquerel, and of radium, 

 by M. and Mme. Curie and Beinont. In the light of these 

 epoch-making discoveries we have completely revised 

 our concepts of the nature of matter and of electricity. 

 The atom, the "undivided," has been shattered into 

 fragments, and a large percentage of the investigations 

 in the realm of physics and chemistry now have to do 

 with atomic disintegration and the behavior of the re- 

 sulting products. 



It was Rutherford and Soddy who first proposed the 

 hypothesis that radioactivity is a manifestation of the 

 disintegration of atoms, and this hypothesis, chiefly 

 through the investigations of Rutherford, has already 

 assumed the rank of a theory. 



It would be superfluous to enter here into a detailed 

 account of the nature of radioactivity, as understood at 

 present. Suffice it to say that the theory elaborated by 



1 The investigations embodied in this paper are treated more fully in the 

 author's memoir on "Effects of the Kays of Eadium on Plants" {Mem. 

 N. Y. Bot. Garden, 4. Sept., 1908). It has not been thought desirable 

 to enter into a discussion here of previous researches on the subject, since 

 the literature is fully treated in the memoir. It is a pleasure again to 

 express my indebtedness 1 



gation possible. ' 



