126 REVERSION AND ALLIED PHENOMENA 



suppose, through any germinal defect (as subsequent generations 

 may show), but simply because it was not sufficiently fed, or 

 because it was poisoned, and so forth. The results may be 

 congenital, but they are not germinal ; they are due to defects 

 not in nature, but in nurture. Thus children born in times of 

 famine are sometimes far below the normal human standard, 

 but it is an assumption to ascribe their deficiencies to their 

 inheritance. In short, all cases of arrested development which 

 can be referred to peculiarities of pre-natal or post-natal nurture 

 should be eliminated from the category of "true inborn rever- 

 , - . sion." For practical purposes, in rough-and-ready description, 



Miw* W^i • they may be called reversions, but they are modificational results ; 



rl /U/Ww^vaIi)''' they do not require the hypothesis of the reawakening of latent 

 ancestral characters. It is reducing scientific terminology to 

 an absurdity to describe as a reversion what may be simply due 

 to premature birth or deficient nutrition. 



There is a stage in the development of the human foetus when the 

 openings of the nostrils communicate down the lip with the corners 

 of the mouth-opening ; when this communication, which is normally 

 closed up, persists, we have (in part) the abnormality known as 

 " hare-lip," which is normal in rabbit and hare, and is even more 

 clearly seen in the skate and similar fishes. But there is no reason 

 to interpret the abnormality in man, as a reversion ; it is an arrest 

 at a stage which is normally passed through ; it is probably due 

 simply to a lack of developmental vigour, or more simply still to 

 a lack of adequate nutrition. Dr. Joseph Bell * refers to a case 

 mentioned by Prof. Haughton of young lion-cubs which all died 

 of hare-Hp — the supposed reason of the arrest being that the keeper 

 fed the pregnant lioness on tit-bits, without bones. When the 

 supply of bones was ensured on subsequent occasions, the tendency 

 to hare-lip disappeared. 



In a hornless breed of cattle, derived originally from a horned 

 breed, a calf is born with small horns. This may be plausibly 

 interpreted as a reversion to a horned ancestor. But when a calf 



* "Discussion on Heredity in 'Disea.SQ," Scottish Med. and Surg. Journ. 

 vi. 1900, p. 307. 



