CHAPTER XIII 
DISEASES AFFECTING THE BRAIN AND 
NERVOUS SYSTEM 
AS compared with mau, domestic au:mmals are affected 
by few diseases of the nervous system. This is prob- 
ably due, in part, to the higher development of the 
nervous system in man, as well as to the greater strain 
to which it is subjected. Insanity and the other men- 
tal diseases in man that may be caused by worry and 
excesses, are practically unknown among animals. 
Some of the so-called “nervous diseases’? are merely 
symptoms of other disorders; but, inasmuch as the 
farmer recognizes symptoms as diseases, it has seemed 
best to include in one chapter the common diseases 
that manifest themselves chiefly in the nervous system. 
HYDROCEPHALUS 
Hydrocephalus, commonly called “ water on the brain,” 
sometimes occurs in foals, calves and other young ani- 
mals at birth. The skull is enlarged and the brain is 
largely replaced by a watery fluid. See Fig. 41, Chapter 
IX. Animals affected with this disease seldom live, and 
when they do are of no value. The best plan is to 
destroy them at once, as there is no treatment known 
that is satisfactory. 
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