TRANSMISSION OF MALFORMA TIONS. 1 89 



in a family, but do not reappear so constantly to become 

 as it were, a matter of entail. This may be in part ex- 

 plained, perhaps, by the fact that attempts are not made 

 to propagate the malformation, as is done in domesti- 

 cated animals. 



The frequent and familiar malformation known as 

 hare-lip and cleft palate is not by any means confined to 

 the human species, but occurs in horses, calves, sheep, 

 dogs, and even lions. In the human subject it has been 



FIG. 100. The nose and lip of a 

 Hare, showing the cleft. 



FIG. 101. The nose of a 

 Dog, showing the median 

 furrow. 



known to affect several members of the same family, and 

 to occur in the offspring of the affected members. The 

 defect takes the name hare-lip because the hare, in 

 common with a few other mammals, exhibits a median 

 cleft in its upper lip. This cleft in the hare is an exagge- 

 ration of the furrow which is present on the upper lip 01 

 many mammals, and extends on to the nose (figs. 100 and 

 101). In children affected with hare-lip the cleft is rarely 

 situated in the middle line, but to one or other side ; 



