38 Heredity. 



Some persons cannot bear the contact or even the near presence 

 of certain objects, such as silk or cork. This morbid sensibility 

 is often transmitted by one or other of the parents. ' We are 

 acquainted with a family, several members of which, both boys 'and 

 girls, experience instinctively, on touching cork, or the downy skin 

 of a peach, such an internal sensation of shuddering repulsion that 

 the very sight of the fruit is unendurable to them ; which, therefore, 

 must be given them with the skin removed.' l 



Here we may refer, in passing, to certain hereditary anomalies, 

 such as polydactylism, and the warty membrane of Edward 

 Lambert (of which we have already spoken), both of which cases 

 belong rather to the physiological side of the question. r 



The hand, which is pre-eminently the organ of touch, is modified 

 by heredity. ' That large hands are inherited by men and women 

 whose ancestors led laborious lives ; and that men and women 

 whose descent, for many generations, has been from those unused 

 to manual labour commonly have small hands, are established 

 opinions.' 2 



The same is true of left-handed persons. There are families 

 in which the special use of the left hand is hereditary. Girpu 

 mentions a family in which the father, the children, and most of 

 the grandchildren were left-handed. One of the latter betrayed 

 its left-handedness from earliest infancy, nor could it be broken 

 of the habit, though the left hand was bound and swathed. 



II. OF SIGHT. 



Sight is the noblest, the most intellectual, of all tne senses, and 

 the most important for science and aesthetics. It is a known fact 

 that accidental blindness may lead to insanity. Congenital blind- 

 ness certainly influences the mind : the imagination of one born 

 blind, which possesses only tactile sensations, cannot be anything 

 like ours, in which visual sensations predominate. Hence, from a 

 purely psychological point of view, the heredity of the sensorial 

 modes of vision is worth studying. 



The individual varieties of this sense may be classed under 

 three heads, accordingly as they depend on mechanical causes, or 



1 Lucas, i. 481. 2 Spencer, Biology, vol. i. 82. 



