212 



Heredity and Environment 



Hoppe believes that a single drunken debauch may so injure 

 the germ cells of man as to produce abnormal and defective off- 

 spring, though this is by no means proved; while Hertwig con- 

 cludes that the great prevalence of the drug habit may seriously 

 affect the germ cells and their subsequent development. Forel 

 has for many years maintained that one of the most serious causes 

 of human malformations and degenerations is to be found in the 

 effect of alcohol on the germ cells, especially at the time of con- 

 ception. 



FIG. 74. DWARFED GUINEA-PIGS ON THE LEFT AND NORMAL ONES ON THE 

 RIGHT. All are of approximately the same age though the normal ones 

 are nearly twice the weight of the dwarfs. The normals came from nor- 

 mal parents, the dwarfs from a normal mother and an alcoholic father; 

 the dwarfing has therefore been produced by the influence of alcohol on 

 the spermatozoa. (From Stockard.) 



