CORRELATION OF ORGANS. 243 
those changes of animals and plants which give rise to an 
absence of pigment (noticed previously)—in albinoes. The 
want of the usual colouring matter goes hand in hand with 
certain changes in the formation of other parts; for example, 
of the muscular and osseous system, consequently of organic 
systems which are not at all ultimately connected with 
the system of the outer skin. Very frequently albinoes are 
more feebly developed, and consequently the whole structure 
of the body is more delicate and weak than in coloured 
animals of the same species. The organs of the senses and 
nervous system are in like manner curiously affected when 
there is this want of pigment. White cats with blue eyes 
are nearly always deaf. White horses are distinguished 
from coloured horses by their special liability to form sarko- 
matous tumours. In man, also, the degree of the development 
of pigment in the outer skin greatly influences the suscepti- 
bility of the organism for certain diseases; so that, for 
instance, Europeans with a dark complexion, black hair, 
and brown eyes become more easily acclimatized to tropical 
countries, and are less subject to the diseases there prevalent 
Gnflammation of the liver, yellow fever, etc.) than Europeans 
of white complexion, fair hair, and blue eyes. (Compare, 
above, p. 150.) 
Among these correlations in the formation of different 
organs, those are specially remarkable which exist between 
the sexual organs and other parts of the body. No change 
of any part reacts so powerfully upon the other parts of the 
body as a certain treatment of the sexual organs. Farmers 
who wish to obtain an abundant formation of fat in pigs, 
sheep, etc., remove the sexual organs by cutting them out, 
(castration), and this is indeed done to animals of both sexes, 
