2 Heredity. 



consider this latter subject at the outset This we will do very 

 briefly, referring the reader for fuller details to special treatises. 

 It will suffice to show, by means of a few definite and well-ascer- 

 tained facts, that heredity extends over all the elements and 

 functions of the organism ; to its external and internal structure, 

 its maladies, its special characteristics, and its acquired modifi- 

 cations. 



The first thing that attracts the attention, even of the un- 

 observant, is the heredity of the external structure. This is a fact 

 of everyday experience, and nothing is more common than to 

 hear that such and such a child is the image of its father, mother, 

 or grandparents. Hereditary influence may manifest itself in the 

 limbs, the trunk, the head, even in the nails and the hair, but 

 especially in the countenance, expression, or characteristic features. 

 This is an observation made by the ancients ; hence the Romans 

 had their Nasones, Labeones, Buccones, Capifones, and other names, 

 derived from hereditary peculiarities. According to Haller, the 

 Bentivoglios had on their bodies a slightly prominent tumour, 

 transmitted from father to son, which warned them of changes 

 in the weather, and which grew larger whenever a moist wind 

 was coming. The resemblance may be so close as to give 

 rise to doubts concerning personal identity, or at once to betray 

 parentage. Ten years before his death a singer at the opera, 

 named Nourrit, appeared on the stage with one of his sons, 

 who had inherited his physical constitution as well as his pleasing 

 voice ; and in a play with a plot like that of the Mencechmi, the 

 extraordinary resemblance of the son to the father added a 

 hundred-fold interest to the endless misunderstandings with which 

 the play was filled. 1 These hereditary resemblances have some- 

 times led to the most unexpected and most romantic adventures, 

 so that it is not surprising that Marryat has turned them to 

 account in his novel, 'Japhcl in Search of a Father. 1 



It is still more singular that this resemblance between parents 

 and children may undergo such metamorphoses as shall cause the 

 child to resemble at one time the father, and at another the 



1 P. Lucas, Traitf Fhysiologique et Fhttosophiqite de nieredile 

 vol. i. p. 195. 



