TUMORS OF DOMESTIC ANIMALS 23 
finally metastatic deposits. Sarcomas have no lymphatics or nerves, 
according to most authorities. This is the reason that metastases of 
sarcomas take place by the blood vessels rather than the lymph 
channels, except in lymphosarcoma. 
Combinations, — Sarcomas may combine with many other neo- 
jDlasms. The combination with fibromas is very common in all 
domestic animals. All gradations of fibrous tissue, from a mere 
trace to a decided excess, may take place. The development of 
fibrous tissue in a sarcoma has a tendency to make the sarcoma less 
malignant. In naming these combinations, the name of sarcoma is 
invariably used last, as in fibrosarcoma, chondrosarcoma, osteosar- 
coma, myxosarcoma, etc. 
Degeneration. — Nearly every form of degeneration may affect sar- 
comas, especially the more rapidly growing varieties. Fatty degen- 
eration, liquefaction, necrosis leading to the formation of cysts, and 
ulceration are more common than mucoid degeneration, hyaline de- 
generation, caseation pigmentation, or amyloid degeneration. It is 
also customary to speak of angiomatous change, cavernous change, 
telangiectatic change, fibrous change, etc. These terms denote no 
special change of degeneration, but are used simply to express the 
combination of the sarcoma with the other tissue by a different name. 
Sarcomatosis is a condition characterized by the formation of mul- 
tiple sarcoma deposits in the skin or in the internal organs. Sarco- 
matosis in fowls is somewhat common. 
SPINDLE-CELL SARCOMA 
Spindle-cell sarcoma is a very common neoplasm in man and in 
the domestic animals. The neoplasms vary in size, usually grow- 
ing slowly as a single mass, but may be multiple when they grow 
more rapidly. The cells are either small or large, spindle shaped, 
elongated, tapering toward the ends. The cells of the small spin- 
dle-cell sarcoma are from 10 to 20 microns in length, or approxi- 
mately one and one-fourth to three times as long as the diameter 
of a red blood corpuscle (human). The cells resemble fibroblasts. 
Dense connective tissue in the skin, the fascias, perichondrium, and 
periosteum are some of the places in which spindle-cell sarcomas 
most frequently grow. These neoplasms may be very cellular, or 
may have so much fibrous tissue as to simulate a fibrosarcoma. 
Such neoplasms are frequently called intermediate types. 
The cells in the small spindle-cell sarcoma are usually uniform in 
size, compactly arranged in interlacing bundles or fasciculi, with 
very little intercellular substance between them. The nuclei are 
oblong, not so long as the nuclei of involuntary muscle, but longer 
than those in fibroblasts. In sections the interlacing bundles of 
spindle cells are cut at various angles to the axis of the cells, giving 
the impression that spindle-shaped cells, oval cells, and round cells 
are intermingled. It is important not to consider this appearance 
as a mixed type of spindle-cell and round-cell variety of sarcoma. 
The cells take the nuclear stains well unless degenerative changes 
are present. These neoplasms are grayish white in color, moderately 
firm, and not very vascular. They grow very slowly, but may be- 
come very large. Small spindle-cell sarcomas, as a rule, are less 
malignant and less prone to give metastasis than other varieties of 
