78 MARRIAGE AND DISEASE. 



V. HEREDITY OF INFLUENCE. This is seen when the 

 child of a second marriage resembles the husband of 

 a previous marriage; as, for example, when a white 

 woman has had children by a first husband who was a 

 negro, and afterwards has children by a second hus- 

 band, who is of white blood, and the children by this 

 second marriage show distinct evidence of the presence 

 of characters peculiar to the negro. It appears that 

 the male who first impregnates a female, so impresses 

 the organism of that female that the young she bears 

 to other males will more or less " favour " him who 

 first impregnated the mother. This is well known to 

 the breeders of animals, who are most careful not to 

 permit the approach of chance males, as the influence 

 of such a cross will frequently be observable in many 

 following, pregnancies by other males. Nor are we 

 without evidence of the working of this law in the 

 human family ; but, as far as man is concerned, it is of 

 no importance except to the medical jurist, whom it 

 sometimes aids in deciding paternity. 



These, then, may be taken as the so-called laws of 

 heredity, which have been formulated to include most 

 of the phenomena met with in families. They are but 

 arbitrary divisions of the one great law or principle, 

 and may be increased in number, or varied, at will. 

 Some writers go further in their classification of heredi- 

 tary phenomena, and make a large number of divisions 

 and sub-divisions ; but this serves no good purpose, and 

 often only tends to confuse the student. There is, 

 however, one class of cases which, while not deserving 



