DISEASES OF THE BRAIN. 295 



cephalus are very rare, even in the mildest forms of the 

 disease. 



Morbid Anatomy. — The ventricles are found distended 

 with a varying quantity of clear limpid or slightly yellow 

 or greenish serum. The lining membrane of the sac is often 

 rough and granular. The quantity of fluid varies very con- 



Fig, 4. — Head of Hydrocephalic Foal (from Fleming's 'Veterinary 

 Obstetrics.' 



siderably, but is generally from two to four pints in the foal 

 and calf. 



The late Mr. D. Gresswell collected as much as five 

 and a half pints in one instance, and over eleven in 

 another. 



The largest amount recorded is two and a half gallons. 



The accumulation of the fluid within the ventricles flattens 

 the cerebral convolutions, and may almost entirely obliterate 

 them, and the hemispheres are more or less completely 

 destroyed. 



The spinal cord, choroid plexuses, and cerebellum are not 

 generally aff'ected. 



