88 
ON THE BLAIN. 
The primary seat of the disease is the cellular substance 
beneath the integument of the part. As the sublingual glands 
lie along the under part of the tongue, and their ducts open on 
the side of the fraenum, it is possible that this disease may pro¬ 
ceed from, or be connected with, obstruction or inflammation of 
these ducts. Dissection, however, has not proved this; and the 
seat of disease, when the swellings are first discovered, is the 
cellular tissue between the integument and the lateral parts of 
the tongue chiefly, and between the membrane of the mouth 
and the sublingual glands partly: in cattle, however, the inflam¬ 
mation soon spreads to all the neighbouring parts. 
Post-mortem examination shews intense inflammation or even 
gangrene in this situation, and also of the oesophagus, the rumen, 
and the fourth stomach. The food in the rumen has a most 
offensive smell, and that in the maniplus is hard and dry. The 
small intestines are highly inflamed, with red and black patches 
in the caecum, colon, and rectum. 
Of the cause of this disease I cannot speak with confidence: 
it may arise from, or be connected with inflammation or obstruc¬ 
tion in the ducts of the sublingual glands; but I suspect that, in 
the great majority of cases, it has another, although at present 
unknown origin. 
It does not appear to depend on the food, for the stall-fed 
cows of the metropolis are as subject to it as the grazing cattle 
of the country. 
There is no disease of which it is the necessary or general 
companion. I have seen it in tetanus in the horse, and have 
oftener observed it in severe catarrh, but still oftener there has 
been no other recognizable malady. In the dog I could never 
tra^e it as the sequela, or concomitant of another disease. In 
cattle it either ceases before the constitution is much affected, if 
proper means have been taken, or it is succeeded by or dege¬ 
nerates into typhus. 
It is more frequent in spring and autumn than at other seasons 
of the year: these are seasons when the animal is debilitated 
by the process of moulting, and more than usually disposed to 
inflammatory complaints. 
It is generally epidemic, Many cases occur about the same 
time in certain districts, or over a great extent of country. When 
it appears in the town dairies, the country ones are rarely exempt 
from it. 
It is contagious in cattle, and most ruinously so when it 
assumes the malignant character. The farmer and the dairy¬ 
man cannot have this too deeply impressed upon their minds. 
There must, however, be actual contact; the beasts must eat 
