TUMORS. 214 
channels (sarcomas) ; others extend along the lymphatic vessels and stop 
at the first group of ganglia they reach (epithelial cancer); and others 
advance rapidly into the lymphatic vessels, and by a very active pullulation 
are soon spread over most of the viscera (encephaloid cancer). It is 
known that tumors that are rich in cells but little developed, and greatly 
resembling embryonic forms, are the most malignant and infectious. 
With tumors of the same nature (carcinomas, sarcomas, or melanomas) 
the gravity and the tendency to generalization are almost always in direct 
proportion to the rapidity of development of the primitive tumor. Gener- 
ally, in animals, carcinoma grows more slowly than sarcoma, although in- 
fecting little by little the lymphatics that sarcoma would respect. The 
skin is less often attacked by subcutaneous sarcoma than by carcinoma ; 
its ulceration also is more rare and slower. Although while encephaloid 
carcinomas are seen developing very rapidly, and sarcomas remain local- 
ized for months, even for years, without disturbing the general health, it 
is nevertheless true that sarcomatosis develops more rapidly as a rule. 
The dog, of which we spoke above, affected with sarcoma of the penis, 
died from extensive lesions three months after the appearance of the origi- 
nal neoplasm ; 2,200 tumors were counted on the surface of the lungs. 
The prognosis of neoplasms, extremely variable, depends upon their 
nature, their seat, the rapidity of their growth, the integrity or invasion of 
the surrounding lymphatics, and the general state of the patient’s health. 
Microscopical examination does not always allow the making of a prognosis 
in a positive manner. Exceptionally one will meet with fibromas of rapid 
growth and of a spreading tendency, and with others that recidivate. 
Epithelial tumors with nearly similar histological characters have been 
seen acting in different ways—some developing very slowly and remaining 
local, others spreading, recidivating and infectious. On the other hand, 
tumors truly malignant according to their histological characters have been 
observed whose cure was brought about by early and complete removal. 
At any rate, a determination of the nature ofa certain number of tumors 
by microscopical examination is somewhat difficult for one who has not 
made a special study of that portion of pathological anatomy. 
In general, whatever may be the nature, age and seat of tumors, adlation 
or destruction by caustics is the only efficacious mode of treatment. For 
benign growths, the interference of the surgeon varies according to the 
clinical character of the neoplasm and the region it occupies. It is pru- 
dent to leave alone indolent, stationary or slowly progressing tumors loca- 
ted in regions where they give rise to no inconvenience. If they are, 
however, well pedunculated, they can be removed with the ecraseur or a 
non-extensible ligature. If they are small and do not spread at their base, 
the red-hot iron or potential caustics (potash, chloride of zinc, arsenious 
