222 THE POPULAR SCIENCE MONTHLY 



THE INFLUENCE OF EADIUM RAYS ON A FEW LIFE 



PROCESSES OF PLANTS^ 



By Professor C. STUART GAGER 



UNIVERSITY OF MISSOURI 



THE purpose of the present paper is to present in non-teclmical 

 form some of the more striking results embodied in the author's 

 memoir on " Effects of the Rays of Radium on Plants."^ 



It is now well known that radioactivity was discovered by Henri 

 Becquerel in 1896. Earlier in this same year Niewenglowski had 

 found that several substances, after being exposed to sunlight, gave off 

 a new kind of rays that could penetrate matter opaque to ordinary 

 light. Following up this work, Becquerel found that the salts of 

 uranium gave off such rays, even when not exposed to sunlight. 

 Uranium, he said, manifests a kind of " invisible phosphorescence." 

 It was Madame Curie who, in 1898, proposed the term " radioactive " 

 for substances possessing this property. In 1898, also, M. and Mme. 

 Curie and Bemont announced the discovery of a new substance forte- 

 ment radio-active, contained in pitchblende. In a moment of inspira- 

 tion they named it radium. 



The discovery of radioactivity and of radium introduced a new 

 epoch into physical science. Not only was it necessary to revise old 

 ideas and ways of expressing them, but new ideas and conceptions, and 

 a new scientific jargon all developed in less than a decade. Atom, 

 affinity, opaque, ray, electricity, matter and other more or less funda- 

 mental terms had to be redefined. To the layman, getting his science 

 largely from the daily press, it was revolution; but to the patient 

 worker in the laboratory it was evolution. He welcomed the new 

 light as the sure reward of years of patient interrogation of nature; as 

 the culmination of a long series of painstaking investigations. 



Through the further classical researches of the two Curies, of 

 Rutherford, Righi, Soddy, Becquerel and many others, the new science 

 of radioactivity rapidly developed. The term atom became a figure of 

 speech; matter and electricity became difficult to distinguish from each 

 other, and what remained of scientific materialism received a blow 

 from which it may never recover. 



It need hardly be restated here, that radioactivity is an expression 

 of the disintegration of atoms. The atom of radium is constantly 

 breaking up and hurling into space minute particles at enormous 



^ Contributions from the Botanical Department of the University of Mis- 

 souri. No. 16. 



' Mem. N. Y. Bot. Gard., 4 : 1-286, November, 1908, 



