THE CONTROL OF LIFE 107 



stance which attacks the protein of the 

 rabbit's eye it would be natural to ex- 

 pect that the injection of this substance 

 into the rabbit would produce defective 

 eyes. The case is not quite clear, how- 

 ever, since it appears that many poisons 

 affect the eye more quickly than other 

 parts. 



Guyer states that the effect of a single 

 treatment has persisted for nine genera- 

 tions and that there is no reason to sup- 

 pose that it will not go on indefinitely 

 since the imperfections of the eye tend 

 to become worse in succeeding genera- 

 tions and also to occur in a proportionally 

 greater number of young. It seems pos- 

 sible that the material from the defective 

 eye of any individual may get into the 

 circulation of that individual and cause 

 the production there of substances which 

 are destructive to the protein of the eye; 

 if these substances pass into the develop- 

 ing young they might produce defects 

 of the eye. 



In these cases the poisonous agent 



