254 THE MICROSCOPE IN VETERINARY MEDICINE. 
been made have revealed quite unusual and, in many respects, 
very remarkable changes of structure, very little light has 
been thrown upon the cause of the changes which have been 
observed, and, indeed, from the limited number of inspections 
which have been made, it would be unsafe to attempt to 
establish any general conclusions as to the character of the 
structural alterations which occur in many instances of dis¬ 
ease of the bony system. Instructive subjects for inquiry 
present themselves in exostosis, hyperostosis, necrosis, caries, 
fragilitus ossium, and mollitus ossium; at present, we are 
concerned with the latter disease in particular. A remarkable 
instance of enlargement and weakening, as it may be called, 
of the bony structure is recorded in the ^ Veterinary Record^ 
for 1849. The horse which was affected with the disease 
was a miller^s horse,under the care of Mr. Shave, M.R.C.V.S., 
of Chelmsford. Mr. Shave, in relating the history of the 
case, stated that the horse was brought to his infirmary with 
an enlargement of the submaxillary bones. The disease 
continued to advance in spite of treatment, and in six months 
from the time of first being examined by Mr. Shave the 
horse was destroyed as incurable. A post-mortem examina¬ 
tion was made, and the skeleton of the head, which was the 
part most affected, was presented before the members of the 
Veterinary Medical Association. 
Altogether, the aspect of the diseased part was very re¬ 
markable. The whole head was uniformly and even sym¬ 
metrically enlarged to nearly twice its natural size. The 
bones everywhere presented a porous or spongy appearance, 
quite unlike the dense structure of the normal bone. Other 
portions of the skeleton were obtained, and it was then dis¬ 
covered that scarcely a bone of the animaks body was free from 
a similar diseased condition complicated in the bones of the 
extremities, with extensive ulceration of the articular surfaces. 
It unfortunately happened that no microscopic examination 
of the parts was made at the time; but Professor Varnell 
having retained a portion of the jawbone, was in 1860 in¬ 
duced to investigate its structure, and discovered that the 
Haversian canals were dilated, and their surrounding lamellse 
extremely thin.'’"’ The cause of the dilatation it was at that 
distance of time impossible perhaps to determine. 
Other instances of enlargement and softening of the bones 
was recorded by Professor Varnell in the Veterinarian for 
September, 1860. The disease is described as resembling 
in many respects Mollities ossium. Rachitis, Osteoporosis, 
and fatty degeneration of bone; the last term seems to be 
most accordant with the microscopic appearances which are 
