Heredity and Environment 109 



to argue, however, that they do not controvert any of 

 our previous statements, as, in any case, they prove 

 nothing more than we have admitted: that the individual 

 inherits only the characteristics of the genus from 

 which he was propagated, plus some physical features 

 of his parents or grandparents, which allow of that 

 slight individual variation which exists amongst the 

 different members of every species. In the case of 

 Man, the qualities of mind make the study of this 

 question immeasurably more intricate, but the fact 

 remains in equal degree for him that he inherits the 

 characteristics of the " genus homo sapiens," with some 

 special features, such as colour of eye or hair, shape of 

 head or nose, height or breadth of body, but his ulti- 

 mate condition physically, intellectually, and morally 

 depend entirely upon environment. Dewar and Finn 

 have an illuminating passage which bears on this 

 subject. Writing on the fertilised egg, they say : 

 " Our conception is that it is composed of a number of 

 entities, to which we have given the name ' biological 

 molecules,' because in certain respects their behaviour 

 is not unlike chemical molecules. The units which com- 

 pose these molecules, being made up of protoplasm, 

 are endowed with all the properties of life, including 

 the inherent instability which characterises all living 

 matter." This inherent instability must always be 

 borne in mind in explaining isolated cases of genius on 

 the one hand, or of degradation on the other. We are 

 too often inclined to use the word " reversion," and 

 thus give undue importance to the idea of heredity, 

 when the designation " sport " would be more appro- 

 priate — one of those unstable productions which is 

 characteristic of all living matter. As we have pointed 

 out already, nothing is so evanescent as these indi- 

 vidual variations ; in a state of nature they are imme- 

 diately destroyed by the potent influence of marriage. 



