DISEASES OF THE BRAIN. 293 



Its pathology is obscure, but when occurring in adults, it 

 is probably, as in man, dependent upon pressure on the vena3 

 galeni (D. Gresswell). 



When occurring as a congenital defect, it is probably due 

 to some constitutional cachexia in one or both parents. 



Symptoms. — The symptoms of hydrocephalus may be 

 arranged under two groups : — 



1. The A]jpeamncc of the Head. — The h3^drocephalic head is 

 recognised by the great enlargement of the volume of the 

 cranium. 



The face appears very small by contrast, and the fon- 

 tanelles and sutures are wider than in the normal condition. 



Dr. Fleming, in his excellent ' Text-Book of Veterinary 

 Obstetrics,' gives the following description of this unsightly 

 condition : 



* In some cases the distension has been so slight that the 

 frontal bones are not much raised, while in others the collec- 

 tion of serum has been so great that these and other bones 

 of the cranium are displaced, and the forehead, rising almost 

 at right angles to the face, suddenly reaches an extraordinary 

 height, giving the creature a startling appearance. The 

 hydrocephalic tumour varies in figure as well as in volume. 

 It is sometimes quite globular, and protrudes so high and so 

 much over the face as to give the physiognomy a strangely 

 human appearance ; in rare cases it is narrow, but excessively 

 protuberant, involving only a part of the cranium ; at other 

 times it is bilocular, and the divisions may be either alike or 

 unequal in volume. 



' Not unfrequently the diameter of such a tumour in the 

 calf measures more than half a foot. The tumour is soft 

 and depressible in parts, hard and resisting in others, owing 

 to the bones of the cranium being altered and separated in 

 places. 



* These bones, and particularly the frontal, temporal and 



