70 MARRIAGE AND DISEASE. 



the daughters may escape ; and if the mother be the 

 affected one, while the sons escape, the daughters will 

 be epileptic or scrofulous as the case may be. But if 

 the heredity be of the diagonal order the epilepsy 

 of the grandfather will descend to the mother and 

 through her to the sons, and so on, appearing in 

 different sexes in each succeeding generation. 



Of these two the direct is the mode of transmission 

 of parental characters on the whole the more commonly 

 met with, the sons in most families " favouring " the 

 father, and the daughters the mother ; and this is what 

 we might expect. But there are some family characters 

 which are said to be much more commonly transmitted 

 by the diagonal than the direct. Among such 

 characters are physical deformities and other imperfec- 

 tions of development, as deaf-mutism, hare-lip, squint, 

 club-foot, supernumerary digits and the like. But 

 although this is generally accepted, there is very little 

 evidence to support it, and I am inclined to doubt 

 whether even in these particular cases the diagonal is 

 the more common mode of transmission. 



In support of this view, I would remark that such 

 structural peculiarities as have been mentioned above, 

 are much more likely to prove a bar to marriage in the 

 female than in the male, and as these deformities are 

 as frequently if not more frequently met with in the 

 male, therefore they must in a majority of cases be 

 conveyed by direct heredity from the father to the sons. 

 Besides, such peculiarities being a very slight bar to 

 marriage in the male, they are consequently more likely 



