TRANSMISSION OF CHARACTERISTICS 91 



latent form. This must have been so in the case of 

 cue twins mentioned by Darwin, who, unlike their 

 parents, had both their little fingers crooked and a 

 tooth in the upper jaw misplaced. The "latent 

 germ" indeed is one of the most important features of 

 heredity. It is known that a game-cock may trans- 

 mit his courage through his female to his male off- 

 spring, while diseases such as hydrocele, necessarily 

 confined to the male sex, may be transmitted by a 

 man through his daughter to his grandson. Farmers, 

 it may also be noted, take care to employ for breeding 

 purposes a bull descended from a good milking cow. 

 Lucas quotes cases of hereditary fecundity in families 

 existing sometimes on the mother's, sometimes on the 

 father's side, and proves the existence of a similar law 

 in regard to longevity and short life. There are persons 

 extremely sensitive to contact with silk, cork, the 

 skin of peaches, and other objects. This peculiarity 

 is not the result of caprice or fancy ; it is hereditary. 

 So also is sensitiveness to tickling, which in some per- 

 sons may produce syncope. Short sight, when caused 

 by overwork, is said to pass from parent to child. It 

 is alleged that an eye affection, from which watch- 

 makers and engravers suffer, repeats itself in their 

 children, notwithstanding that these may be brought 



