382 FiETAL DYSTOKIA. 



siderable quantity of fluid in the cranium of the foetus, leading to a 

 proportionate enlargement of that region. 



This diseased condition is not at all uncommon in the Bovine and 

 Equine species, and some of the specimens of craniums found in museums 

 are wonderfully deformed, through the accumulation of fluid in their 

 interior. 



Pathological Anatomy. 



This diseased condition is recognised by a more or less exaggerated 

 development or volume of the cranium, the vault of which has been 

 elevated and distended by the fluid collected in the brain ventricles. 



In some cases the distention has been so slight that the frontal bones 

 are not much raised ; while in others the collection 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 shape as well as in volume. It is 

 sometimes quite globular, and protrudes so high and so much over the 



rig. 96. 

 Skull or a Hydrocephalic Calf : the Cranial Bones are partially 



DESTROYED AND DEFECTIVE. 



face, as to give the physiognomy a strangely human appearance (Fig. 99); 

 in rare cases it is narrow, but excessively protuberant, involving only a 

 part of the cranium (Fig. 100); at other times it is bilobular, 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 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 parietal — are, 

 as a rule, considerably deformed and thrown out of their natural posi- 

 tion, and in places so expanded and rarified as to be no thicker than 

 tissue-paper ; when the internal distention has been very considerable, 

 so that their borders do not meet as in their normal condition, but are 

 often widely separated, leaving between them vast fontanellge occupied 

 only by a thin translucid membrane — the dura mater, which is in im- 

 mediate contact with, and adheres closely to, the skin. 



In some instances — especially in the Calf^the bones in their upper 

 part do not join at all, and the roof of the cranium — or, rather, of the 



