224 DISEASES OF THE HORSE. 
an enlargement of the skull, especially in the region of the forehead. 
The pressure of the fluid may cause the bones to soften. The dis- 
ease is incurable and usually fatal. 
Internal hydrocephalus is a disease of mature horses, and consists 
in the accumulation of an excessive quantity of fluid in the cavities 
or ventricles of the cerebrum. The cause of this accumulation may 
be a previous inflammation, a defect in the circulation of blood 
through the brain, heat stroke, overwork, excessive nutrition, or long- 
continued indigestion. Common, heavy-headed draft horses are pre- 
disposed to this condition. 
Symptoms.—The symptoms are an expression of dullness and stu- 
pidity, and from their nature this disease is sometimes known as 
“dumminess” or “immobility.” A horse so afilicted is called a 
“dummy.” Among the symptoms are loss of intelligence, stupid ex- 
pression, poor memory, etc. The appetite is irregular; the horse may 
stop chewing with a wisp of hay protruding from his lips; he seems 
to forget that it is there. Unnatural positions are sometimes as- 
sumed, the legs being placed in clumsy and unusual attitudes. Such 
horses are difficult to drive, as they do not respond readily to the 
word, to pressure of the bit, or to the whip. Gradually the pulse 
becomes weaker, respiration becomes’ faster, and the subject loses 
weight. Occasionally there are periods of great excitement due to 
temporary congestion of the brain. At such times the horse becomes 
quite uncontrollable. A horse so afflicted is said to have “staggers.” 
The outlook for recovery is not good. 
Treatment is merely palliative. Regular work or exercise and 
nutritious feed easy of digestion, with plenty of fresh water, are 
strongly indicated. Intensive feeding should not be practiced. The 
bowels should be kept open by the use of appropriate diet or by the 
use of small regular doses of Glauber’s salt. 
TUMORS WITHIN THE CRANIUM. 
Tumors within the cranial cavity and the brain occur not infre- 
quently, and give rise to a variety of symptoms, imperfect control of 
voluntary movement, local paralysis, epilepsy, etc. Among the more 
common tumors are the following: 
Osseous tumors, growing from the walls of the cranium, are not 
very uncommon. 
Dentigerous cysts, containing a formation identical to that of a 
tooth, growing from the temporal bone, sometimes are found lying 
loose within the cranium. ; 
Tumors of the choroid plexus, known as brain sand, are frequently 
met with on post-mortem examinations, but seldom give rise to any 
