PATHOLOGICAL ANATOMY OF DOMESTIC BIRDS. 585 
birds. They are apt to pass on to mammalia, and cause to horses 
which have been kept near the roost, a disease similar to the mange 
in that animal. 
II. Bones and Muscles. 
Diseases of the bones, properly speaking, are of rare occurrence 
in birds. With the exception of fractures, and these in birds which 
fly but little, are of no great consequence; but the case is different 
with those who are much on the wing, inasmuch as the air-cells of 
the lungs communicate with the hollow tubes of the long bones: 
by their fracture the air escapes, and it becomes a matter of great 
difficulty for the bird to support its weight in the atmosphere, 
though the fractures only interest the leg or thigh, and the wings 
are intact. With this exception, the consequences and cure are 
the same as in other animals. A wasting of the bones has been 
observed in the common fowl when, during the laying season, 
thev have not been allowed free access to chalk or other calcareous 
substance for any considerable length of time. 
The Muscles are sometimes found to be knotty ; but the nature 
and cause of this affection are unknown. 
III. Digestive Organs; 
The crop of the gallinacce , peacock, turkey, guinea-fowl, common 
fowl, and pigeon, is subject to over-distention. This may arise 
from over-feeding, or from the nature of the food, particularly if 
it consist of grain undergoing fermentation, and germination, 
causing it to swell. This is more frequently the case with peas, 
on which pigeons are much fed. The distention is sometimes so 
great, that it causes a rupture of the parts. In this case the crop 
may be emptied, and the ends of the wound brought together by 
stitches; but this is best prevented by making an incision, and 
treating it in the same way, which gives a better chance of suc¬ 
cess. 
TAUSCH communicates a case of a goose, the oesophagus of which 
was found distended and crammed with food; the stomach was 
empty, but a needle was found crosswise in the gullet. This had 
caused obstruction. The mucous membrane was much swollen and 
inflamed. 
The Pleura and Peritoneum are subject to the same affec¬ 
tions as those of the mammalia, and these have nearly the same 
termination : dropsy and the formation of false membranes have 
been observed. Exudative inflammation I have found so exten¬ 
sive in fowls and ducks, that the whole of the viscera have been 
discovered strongly connected together by adhesions of the plaster 
