78 HEREDITY 



impossible to form any decision as to the appli- 

 cability of this hypothesis. 



Certain other transmissions of acquirements are 

 compatible with Weismann's theory of the germ- 

 plasm, but they may be mentioned only to be 

 dismissed. The first of these, the influence of 

 "maternal impressions," is of interest, because it 

 serves to illustrate an important distinction. 



We have already spent much space in observing 

 the manner in which we may isolate, for purposes of 

 thought, any entity, and then study its relations to 

 all else. Now when the male and female nuclei 

 have united to form the " segmentation-nucleus " — 

 so called since its segmentation will give rise to a 

 new individual — there is plainly offered for considera- 

 tion a distinct entity — the embryo. This also has 

 its environment — the body of the mother. Nothing 

 is truly innate or inborn in the embryo save what 

 was present — as we say, " in embryo " — in the seg- 

 mentation-nucleus. By an absurd and childish con- 

 fusion of thought, we persist in attaching quite 

 undeserved importance to the birth of any of the 

 animals which are brought forth " alive." ^ Hence 

 we speak of any character present at birth as con- 

 genital — which is etymologically justified; but we 

 proceed to assume that congenital is synonymous 

 with inherent or germinal. From our present point 

 of view, it is an irrelevant detail that a young mam- 

 mal happens to leave its mother at the ninth week 

 or month. During the whole period that it spends 

 within its mother, it is to be regarded as an indi- 

 vidual organism, with its own environment. If that 



^ As if a bird's egg were not alive I 



