348 
H. F. PALMER. 
BENIGN TUMORS AND CYSTS. 
By H. F. Palmer, B. S., D. V. S., Veterinarian to Parke, Davis 
& Co., Detroit, Mich. 
Read at the Michigan Veterinary Medical Association at its annual meeting at Lansing, 
Feb. 5th, 1901. 
A tumor is any circumscribed enlargement or swelling or 
any disease in which portions of the body depart from their 
normal form by an unnatural increase in size. It is also more 
restricted and is applied only to those new formations of obscure 
origin which, after appearance, remain either as permanent or 
progressive productions. 
Tumors are of two kinds—benign and malignant. A be¬ 
nign or non-malignant tumor is one which, if allowed to remain, 
is capable of doing injury only by its bulk and pressure, or 
which, if removed, exhibits no tendency to return. 
A malignant tumor is one which proves destructive to the 
tissue in which it is located, which tends to contaminate adjoin¬ 
ing glands or to be disseminated through the blood vessels, in¬ 
cluding changes unfavorable to the proper nutrition of the body. 
After removal they manifest a tendency to recur either at 
the original seat of the disease or in another part of the body, 
and are capable eventually of destroying life. The number of 
malignant as compared to the number of benign tumors is for¬ 
tunately small. 
The benign tumors do not materially differ from the nature 
of the tissue in which they fix their habitation. A lipoma, 
which is a neoplasm of fat, is in most respects identical with 
the surrounding adipose tissue, and a fibroma is only a localized 
hypertrophy of the connective tissue in the midst of which it is 
lodged. Malignant tumors, on the contrary, embody in their 
structure histological conditions altogether unlike the perfected 
tissue in which they grow. 
The following considerations will help us to differentiate the 
two kinds of tumors. Malignant tumors are solitary and recur 
after extirpation. Benign tumors have not the glandular infec¬ 
tion and do not infiltrate into other tissues. Benign tumors 
