76 GENETICS 



as a "document," long rows of labeled bottles contain- 

 ing the fifteen hundred and ninety-two martyrs to 

 science which made up the twenty-two generations of 

 mice in this famous experiment. 



Blaringhem, it is true, obtained mutations which 

 bred true from latent buds that were forced into devel- 

 opment following mutilation of normal buds, but 

 Griffon has shown that similar mutations occur with- 

 out preceding mutilations so that this, as Shull points 

 out, is simply a case of segregation of biotypes already 

 present in the mutilated parent. 



Conklin has hit the nail upon the head with respect 

 to mutilations by saying: "Wooden legs are not in- 

 herited, but wooden heads are." 



b. Environmental Effects 



Trees deformed by prevailing winds, like the willows 

 that line the canals in Belgium and Holland, or storm- 

 crippled trees along the exposed seacoast are not 

 known to produce a modified progeny when their ad- 

 verse environmental conditions are removed. Simi- 

 larly, the persistent sunburn of Englishmen long resi- 

 dent in India does not reappear in their children born 

 in England. 



Sumner kept mice in a constant but abnormally high 

 temperature of 26 C. with the result that the ears, 

 tail, and feet grew noticeably larger than in control 

 animals kept in ordinary lower temperatures, while at 

 the same time the general hairiness of the body de- 

 creased. It should be remembered, however, that mice 



