THE CONTROL OF LIFE 105 



mal animal with the same result and so 

 on until the original cancer had been 

 transplanted eleven times in succession. 



Much more efficient than crude tar is 

 the distillate which comes off when tar 

 is heated to over 300° C. An ether ex- 

 tract is also efficacious and likewise a 

 watery extract of soot which has been 

 mixed with lime. 



The question arises whether it is pos- 

 sible to affect the germ cell so that it will 

 take on new characteristics which will 

 be shown by its descendants. There is 

 considerable evidence that this is the case. 

 When alcohol is given to chickens or 

 guinea pigs, as in the experiments of 

 Pearl and Stockard it affects the germ 

 cells so that the characters of the off- 

 spring are altered and this persists for 

 two or more generations. In the case of 

 guinea pigs the offspring of parents 

 treated with alcohol are less vigorous 

 and have a high death rate. Their eyes 

 show abnormalities and they are in other 

 ways defective. It would appear that 



