224 THEORY AND PRACTICE 



feature makes it difficult to operate. These tumors often break 

 down and granulate, going on to ulceration. 



Colloid degeneration frequently takes place in tumors, espe- 

 cially in epithelial tumors. The colloid material is amber-colored 

 and resembles half melted glue in consistency. Other forms of 

 degeneration are the mucoid and the contents may become very 

 fluid, forming a cyst. 



Of the connective tissue tumors which become malignant the 

 sarcoma is the most common type. The tumor cell is a round 

 cell or spindle shaped. The round celled sarcomata are the 

 m.ost malignant. These tumors are very prone to metastasis. The. 

 so-called melanotic cancer is a type of sarcoma. Each cell con- 

 tains an abundance of pigment, which is often of so great amount 

 that the form of the cell, its nucleus, etc., cannot be made out. 

 The pigment may invade the intercellular substance as well. 

 These black tumors have every feature of malignancy. Some- 

 times they develop very suddenly, producing great lameness. No 

 tissue m the body is exempt from them, but their favorite sites 

 are the vulva, the anus, and the bare part under the tail. When 

 removed, they come back in some other part. They are found 

 most frequently in old white horses. 



The epithelial cancer is common. This tumor is composed 

 of epithelial cells, which can be of any type. The tumors may 

 grow and develop in the skin and mucous membrane or in the 

 glands. Metastasis usually follows and even though the tumor 

 be removed, it will most always recur. 



A benign tumor usually is surrounded by a capsule. It may 

 consist of fat, cartilage, fibrous connective tissue or bone. 



The fibrous connective tissue tumor is called a fibroma. It 

 may be soft or hard. The polypus is a form of soft fibroma 

 which is usually found in the nose. It is attached by a pedicle 

 and in the horse it may be so long as to interfere with the epi- 

 glottis. It produces a difficulty in breathing, a sort of snoring 

 or snuffling, the same as heard in the pug dog. The best way to 

 remove a polypus is with a wire ecraseur. If the neck of the 

 polypus is small, it can be twisted off with a pair of forceps. 

 After removing, wash out with perchloride of iron — 1 dram to 

 the pint of water — twice a day. Another kind of fibroma is the 



