CANCER IN HORSES. 
433 
The mass of the tumour consisted of simple and compound 
cells, naked nuclei, and a semi-fluid albuminous substance, 
containing molecules and granules in great abundance. Some 
of the compound or “ mother-cells ” were the 600th of an 
inch in diameter. The majority of the ordinary cells varied 
from g 1 ^ th to -j^^th of an inch ; they were either spheroidal 
slightly ovoid in form, and presented that peculiar softness of 
outline so characteristic of cancerous growths. Their eccen- 
tric nuclei were usually so large as to extend two thirds 
across the cell area, and the nucleoli were distinctly marked. 
Acetic acid rendered the cell-walls transparent, and the nuclei 
more distinct. 
I showed the growth to my friend, Dr. W. T. Gairdner, the 
eminent pathologist, who said, no reasonable doubt could 
exist as to its being an encephaloid cancer. Dr. Bennett, 
professor of physiology, and Dr. Haldane, pathologist to the 
Royal Infirmary, also did me the favour to examine this 
structure microscopically, and considered it to present w^eli- 
marked features of encephaloma. 
I am anxious to record these facts, because cancer is com- 
paratively rare in the horse, and home veterinary literature 
furnishes scarcely a case wherein the true character of so- 
called cancer was verified by careful dissection, and examina- 
tion under the microscope. 
Another, and in fact the only other case of cancer which I 
ever saw' and accurately determined, occurred in our practice 
during last summer. The subject was an aged horse belong- 
ing to the Earl of Caithness. He became gradually ill, and 
grew worse and v T orse under some hepatic disease, the nature 
of w hich was doubtful during life. Being useless in other 
respects he was destroyed. The liver, although not weighed, 
was evidently four or five times its natural size, and had formed 
extensive adhesions by its posterior surface to every conti- 
guous viscus. It presented extensive cancerous disease of the 
carcinomatous and encephaloid varieties. This was con- 
firmed by microscopic examination made by Dr. Gairdner 
and m} 7 self independently. 
Malignant growths are remarkably rare in the low r er 
animals. We do, no doubt, see cases that are called cancer, 
but according to my own experience, most of these have 
proved not to be cancer when accurately examined. I have, 
however, seen various cancer cases in the ox, but oftenest in 
the bitch, showing that the disease is more frequent in these 
animals than in the horse. 
Youatt’s description of cancer in the bitch is not precise 
enough to show w hether the mammary tumours he describes 
xxvii. 57 
