248 Kansas Academy of Science. 



true in the tadpoles where the operation had been successfully 

 performed. 



These experiments will certainly lead to a very extensive 

 series of other investigations of similar kind. A large and 

 extremely fruitful field of research is opened up by this work. 



University of Kansas, Lawrence. 



THE RELATION BETWEEN THE GERM CELLS AND 

 THE ENVIRONMENT. 



Bennkt M. Allen. 



THE constitution of the germ plasm is one of the most 

 prominent questions before biologists. This problem has 

 been attacked by the study of cell lineage, deformation, mu- 

 tilation and chemical treatment of eggs before and after ferti- 

 lization ; by a study of the relation between egg and sperm in 

 fertilization, and through it all have run the brilliant develop- 

 ments in the field of cytology and experimental breeding. We 

 have thus come to understand some of the cardinal facts re- 

 garding the mechanism of heredity. 



The individuality of the chromosomes; their occurrence in 

 pairs; the sex chromosomes; sex-linked characters; the fatal 

 results of multipolar division; the explanation of mutations 

 upon the basis of chromosomal defects and mixtures — all of 

 these results have been interpreted to show that the potential- 

 ities of the germ plasm are laid down in the physical structure 

 of the chromosomes. But through all this work we have diffi- 

 culty in estimating fact and theory at their proper value. This 

 has led to our elevating theories to the rank of established 

 truths. Many have come to believe that the germ plasm is 

 aloof from the soma and absolutely proof against any changes 

 that may take place in the environment. 



Without allowing ourselves to dogmatize upon this subject, 

 let us inquire into the nature of the relation between the 

 soma and the germ cells. 



In studying the early history of the germ cells of the verte- 

 brates, I have been struck by the fact that they undergo an 

 orderly migration from analgen, that are often remote, toward 

 the regions where the gonads will ultimately develop. They 

 appear to be guided and stimulated by influences exerted by 

 the body cells. This striking migration of the germ cells re- 



