144 HEREDITY AND EUGENICS 



touched upon here is the vexed question of functional 

 inheritance, which has been fully discussed by 

 MacBride (191 7), and has been considered elsewhere 

 (Gates, 1 921) in some of its evolutionary aspects. 

 The conceptions of Weismann regarding the insula- 

 tion of the germ plasm and its immunity from bodily 

 and environmental influence are now seen to have 

 been too extreme. Recent experiments of Guyer 

 and Smith (1920) are probably of significance in this 

 connection. B}^ injecting into fowls a finel}^ ground 

 suspension of the lenses of rabbits' eyes, the}' ob- 

 tained a serum from the fowl which was then injected 

 hypodermically into pregnant rabbits. The serum 

 contained a cytolysin* which in a few cases more or 

 less completely dissolved the lenses in the eyes of the 

 embryo rabbits, although those of the mother were 

 unaffected. Without any further treatment the 

 condition was intensified in later generations, and 

 was inherited through the male as well as the female. 

 If these results were actually due to the treatment, 

 as seems highly probable, the}^ have an important 

 bearing on the question of functional inheritance. 



* A substance or antibody which produces dissolution of certain 

 cells. 



