Hereditary Diseases of Sheep and Pi<js. 
83 
panicd by specific inflammation, very apt to become perma- 
nently hereditary. 
The scrofuh)Us taint is sometimes so strong as to affect the 
foetus, and lambs are occasionally born with tuberculous dejiosits 
in their lungs and other parts of the body, and with collections 
of pus in and about the joints. During the fcetal state tubercles 
are also sometimes formed on the membranes of the brain, 
causing effusion into its cavities and enlargement of the head, 
which tlms presents a serious obstacle to parturition. This 
state of foetal tuberculosis induces the disease generally known 
as hydrocephalus, or water in tlie head. It is occasionally con- 
genital, but more frequently appears a few weeks or months 
after birth, and is then indicated by the following well-marked 
symptoms. The lamb is dull and stupid, careless about its 
food and impatient of light. It hangs its head, grinds its teeth, 
totters in its gait, and becomes constipated and feverish. The 
head is sometimes much enlarged, especially in young subjects, 
from the soft and yielding nature of their cranial bones. Most 
cases terminate fatally within a lew days, although some run on 
for several weeks. After death, numbers of opaque, yellowish 
white, granular bodies, varying from the size of a pin's head to 
that of a small nut, are found scattered over the surface of the 
pia mater, and apparently sunk into the convolutions of the 
brain, from their following the course of the veins. The substance 
of the brain is often much softened, and serum in greater or less 
amount is found in the ventricles and within tiie arachnoid, 
Avhich becomes opaque, v/hile the other membranes of the 
brain are congested, and sometimes thickened. Minute granules, 
exactly analogous to those within the cranium, are also found in 
other parts of the body, as in the intestinal and bronchial glands, 
and in the lungs. In adults, although not so frequently as in 
lambs, the brain is sometimes the seat of scrofulous deposits, 
usually single or only few in number, and often the size of a 
walnut. Such appearances are not uncommon in pulmonary 
consumption and in rot. 
Tabes mesenterica is a variety of scrofulous disease, sometimes 
occurring in lambs and one-shear sheej). It consists in a deposit 
of tuberculous matter in the mesenteric glands, and is but con- 
sumption affecting the viscera of the abdomen instead of those 
of the chest. It is recognisable by capricious appetite, irregu- 
larity of the bowels, and general wasting and debility. These 
and the other symptoms of the disease depend on impaired 
digestion and assimilation caused by the deposit of thick, 
cheesy matter, in the lacteal vessels and glands. Granular 
matter, of an undoubtedly scrofulous type, is also effused on the 
intestinal mucous membrane, and occasionally upon the peritoneal 
VOL. XVI. D 
