HEREDITARY DISEASES OF HORSES AND CATTLE. 283 
in cattle to take on this disease. A scanty allowance, with 
exposure to cold or wet, or anything else that may disturb 
the balance of the circulation, will induce it when the here- 
ditary predisposition exists. Mr. Youatt was of opinion 
that the practice of breeding from the nearest affinities in- 
duced this disease, and cites as an example that of the Dish- 
ley long-horned breed of cattle, which were notoriously bred in 
this manner, not only by Bakewell, the originator of the 
breed, but also by his successors, — and they were so highly 
disposed to dysentery that it proved the element of their de- 
struction. That the breeding too far, and too incautiously, 
“in and in,” will produce a weakness of constitution that 
predisposes to dysentery, is very probable. A delicacy of 
temperament and form, with a tendency to arrive quickly to 
maturity of bone and muscle, is attained by breeding in this 
manner ; but with these valuable properties a weakness of 
constitution is engendered that renders the cattle less hardy, 
and less capable of withstanding irregularities of living, and 
exposure to vicissitudes of weather. 
A question presents itself here with reference to “ in and 
in 33 breeding, that, in such instances, whatever hereditary 
tendency to disease might exist, is certain to be developed 
in the progeny in its most marked and aggravated forms ; 
and on the same principle will cross-breeding tend to reduce, 
or, may be, remove the disposition altogether. 
The next examples of hereditary tendency to disease, and 
the last w T e shall adduce, are those connected with the eyes 
of horses and cattle. They also, very probably, depend on 
some peculiar state of the blood, involving the same ques- 
tion as gout in the human subject, though perhaps more 
dependent on occasional exciting causes from without. 
(/*.) Constitutional Ophthalmia in Horses, a disease of a pecu- 
liar inflammatory character, showing itself at intervals, and 
especially at a certain period of life — generally from three to 
five years old. When the hereditary proclivity exists, it is 
easily excited by miasms arising from crowded, dirty, and im- 
perfectly ventilated stables. Our case-book and memory 
furnish us with some scores of cases in proof of this. One 
of these is connected with a horse called “ Katerfelto,” that 
served mares in this district some thirty years since. He 
was a favorite stallion with the farmers, and got a very ex- 
tensive and, with the exception of the strong constitutional 
tendency to specific ophthalmia, an excellent stock. Not- 
withstanding so many years have elapsed, yet the disease 
could be accurately traced from him to his descendants, 
handed down through the female line, some ten years since. 
