THE i:n^fluence of eadtum rays oinT germ 



CELLS AND EMBRYONIC TISSUES* 



BY W. C. GEORGE 



Since 1910 there have been some valuable contributions 

 to our knowledge of the influence that radium rays exert on 

 animal tissues. Perhaps the most important of these is Oskar 

 Hertwiii's paper entitled Badiiunl-ranhheit Tierischer Keim- 

 zellen, which I have had occasion to read in the course of 

 some of my own investiiiations in regard to the effects of 

 various changes in the environment on the development of 

 embryos. The results recorded in this paper together with 

 some later results obtained by Oskar Hertwig, his son, Gun- 

 tlier Hertwig, and others, will constitute the basis of my 

 remarks this evening, in which I shall attempt to give you a 

 conception of the present status of our understanding of the 

 biological efl^ects of radio-activity. 



But before proceeding with a consideration of the later 

 discoveries, it would probably be of value to review the 

 discoveries made before 1910. Soon after the discovery of 

 radium in 1908 by Mme. Curie, biologists began to study the 

 influence that Rontgen and radium rays exercise upon ani- 

 mal cells that they strike. The experimenters who studied the 

 influence upon animal cells may be divided into two groups. 

 Those of the first group examined the effect of radiations 

 upon the male- and female sex cells. To this group belong 

 Bohn, Perthes, Schwarz, Schaper, Levy, Bardeen, and others. 

 All of these workers came to the conclusion that radium rays 

 exercise a retarding and injurious eft'ect upon the embryonic 

 processes. Schwarz and Schaper attempted to explain the 

 effect of radium rays by the decomposition of lecithin in 

 the living cell. The American investigator, Bardeen, work- 

 ing with amphibian eggs, found that the period of greatest 

 susceptibility is the period during which there is the most 

 rapid production of nuclear material. 



*Rfa(l before the Medical Society of tlie University of North Carolina. October If.. 1915. 



