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Hereditary Diseases of Sheep and Pigs. 
the patholo<ry of a disease before undertaking its treatment. On 
dissecting the body of an animal that has had an attack of dysen- 
tery, the stomachs are usually found quite sound and healthy 
except the fourth, which is of a light colour, and exhibits extra- 
vasation of blood between its coats. Tlie small intestines have 
a similar appearance, but are not generally ulcerated ; the coats 
of the large intestines ai-e puckered from chronic inflammation 
and contain ulcers of various sizes. In some parts the mucous 
membrane is entirely destroyed, and its place occupied by proud 
flesh. These changes appear to depend not so much on inflam- 
mation as on an impoverished condition of blood and an imper- 
fect nutrition of the parts. As the mucous membranes require 
for their healthy nutrition a great amount of blood, they suffer 
from the impoverishment or vitiation sooner than most of the 
other tissues. This is illustrated in glanders in the horse, as 
well as in the disease under notice. The liver, lungs, and 
mesenteric glands contain tubercles, and occasionally pus, and 
this is one of the many evidences of the close relation betwixt 
dysentery and pulmonary consumption. This relation is further 
borne out by the fact that both occur in the same kind of stock, 
are substituted the one for the other in different individuals of 
the same family, often occur at different times in the same indi- 
vidual, and frequently merge into each other. They are also 
both hereditary, and originate from similar causes, and from 
none more often than from breeding in-and-in, that is, breeding 
from animals near of kin. This system, when judiciously prac- 
tised, causes early maturity and a disposition to grow and fatten 
speedily ; but when followed injudiciously and persisted in for 
several generations, it invariably does much injury, diminishing 
the size and vigour of the flock, rendei'ing the male animals weak 
and incapable of procreating their kind, and the females barren 
or unusually liable to abortion, engendering a disposition to 
dysentery, scrofula, and other malignant diseases, and greatly 
aggravating any previous hereditary tendencies. 
Rheumatism is a peculiar inflammation of serous, fibrous, and 
■fibro-serous tissues, and has the strange disposition to flit about 
from one part to another, now involving some of the larger joints, 
now some of the sheathing envelopes of muscles or tendons, and 
again, as in most fatal cases, the fibro-serous membrane investing 
the heart. In its acute forms it is accompanied by active inflam- 
matory fever, a full, strong, and rapid pulse, and arrestment, 
more or less complete, of all secretion and excretion. In sheep 
it often affects the fibrous coverings of the muscles of the neck 
and back, causing stiffness along with the various symptoms just 
noticed. It is very apt, particularly in its more chronic form, to 
attack the synovial and cartilaginous tissues of the joints, causing 
