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transmission of psychical character presents itself under 

 circumstances that entirely forbid our attributing it to any 

 agency that can operate subsequently to birth, and which 

 it would seem impossible to a.ccount for on any other 

 hypothesis than that the formative capacity of the germ 

 determines the subsequent development of the brain, as 

 of other parts of the body, and (through this) its mode of 

 activity, in accordance with the influences under which 

 that germ was first impregnated. And thus what we speak 

 of as the * original constitution ' of each individual is in 

 great part (if not entirely) determined by the conditions, 

 dynamical and material, of the parent organisms." When 

 alluding to the physiological aspect of heredity, I traced 

 its origin to the fusion of two simple cells, in which were 

 enshrined all its mysteries. But how manifold do these 

 mysteries appear, when, in tracing the source of its psycho- 

 logical aspect, we find it emanating from the same cells. 

 Not only the characteristic physical structure in its every 

 detail, but the mental and moral nature and character are 

 evolved in and transmitted by the fusion of these two 

 infinitesimal cells ! Here is, indeed, a mystery : that by 

 this simple, but occult process, is evolved and transmitted 

 not only the physical, intellectual, and moral likeness of the 

 parents, but of their ancestors, modified not only by the 

 natural tendency to variation which is developed in every 

 child, but by the actual physical and mental condition 

 of the parents at the time of procreation. 



Science, as before remarked, can only record and interpret 

 phenomena and experience ; and although the facts of 

 heredity are indisputable, the ultimate causes remain as 

 inscrutable as ever. She has, therefore, grouped certain 

 phenomena under the name physiological, and others under 



