;86 Heredity. 



should possess with the organism of its own species the instincts 

 of another, would be a monster in the psychological order. The 

 spider can neither have the sensations nor perform the actions of 

 the bee, nor the, beaver those of the wolf. Just so in one and the 

 same species, whether animal or human, the races preserve their 

 psychical, precisely as they do their physiological characteristics. 

 Finally, as regards man, there is not one even of those varieties 

 of the same race which we call peoples that does not present 

 permanent moral characters, when we consider the sum of the 

 individuals. 



Under the specific form, then, mental heredity is unquestionable, 

 and the only doubt possible would have reference to individual 

 characteristics. We have shown from an enormous mass of facts, 

 which we might easily have made larger, that the cases of indi- 

 vidual heredity are too numerous to be the result of mere chance, 

 as some have held them to be. We have shown that all forms of 

 mental activity are transmissible instincts, perceptive faculties, 

 imagination, aptitude for the fine arts, reason, aptitude for science 

 and abstract studies, sentiments, passions, force of character. Nor 

 are the morbid forms less transmissible than the normal, as we 

 have seen in the case of insanity, hallucination, and idiocy. 



Having got at the facts, the next thing was to interpret them, by 

 ascertaining their laws. Here, in the inextricable tangle of con- 

 flicting causes, we reach or>ly a theoretic determination of the law. 

 In practice, however, we can establish a few empiric formulas 

 which enable us to class the facts tolerably well. Thus, heredity 

 is either direct or indirect; now it passes from parent to child, 

 now again it must be referred to some remote ancestor. We have 

 endeavoured to show how the phenomena of atavism, or of rever- 

 sional heredity, may, not inaptly, be compared to alternate gene- 

 rations in lower species ; and how, at all events, those phenomena 

 may serve to give us a correct idea of heredity and of the stubborn 

 tenacity of its laws. 



Passing from the laws to the causes, we have carefully avoided 

 all researches into ultimate reasons, and the only hypothesis we 

 have judged admissible with regard to the immediate cause of 

 heredity is this : psychological heredity has its cause in physiolo- 

 gical heredity, and this in turn has its cause in the partial identity 



