TUMORS AFFECTING CATTLiE. 329 



SOFTENING CYSTS. 



Softening cysts, which result from the degenerative liquefaction of 

 normal or diseased tissues, especially of tumors of different kinds, 

 followed by the encapsulation of the fluid. 



PARASITIC CYSTS. 



Parasitic or foreign-body cysts, due to the inflammatory reaction 

 induced by such parasites as the echinococcus (hydatid cyst) or by 

 the presence of various kinds of foreign bodies. 



EXTRAVASATION CYSTS. 



Extravasation cysts, caused by injuries which rupture blood ves- 

 sels, followed by an increase of fibrous tissue which forms a capsule 

 about the fluid. The hygromata in front of the knee in cattle, so- 

 called tumor of the knee, and serous cysts belong to this variety. 



Hygromata^ or tumors of the knee, — ^These consist in the simplest 

 form of a collection of serous fluid mixed with fibrin within a dis- 

 tended bursa. The walls surrounding the fluid become finn, smooth, 

 and dense. 



Outwardly the tumor appears fluctuating, though tense, while the 

 skin which covers it may be normal, denuded of hair, or covered with 

 hard epidermal scales, possibly half an inch in thickness, forming a 

 hard, horny plate. The cavity which contains the fluid may have the 

 dimensions of a hen's egg, an apple, or a child's head. Its walls are 

 formed by the diseased secreting membrane of the bursal sac, and are 

 readily detachable from the subcutis of the skin. Their internal sur- 

 faces are often uneven or supplied with projections or tufted growths 

 which support a fibrous network within the tumor. 



Tumors of the knee may also assume a granular type, as the result 

 of chronic inflammation or following operative or spontaneous evacua- 

 tion of pus from the part. They are either firmly connected with the 

 skin or are detachable from it, and, when laid open, disclose a whitish 

 red, pork-like tissue surrounding a central nucleus of pus, or a fistu- 

 lous tract leading to the outer surface. They are caused by the 

 chronic inflammation which follows the bruises received by cattle in 

 lying down and in rising or they may be due to falls on uneven, hard 

 ground. 



Treatment fo^r hygromata. — "WHien the swelling first appears cold 

 water should be applied, followed later by bandaging with cloths 

 wrung out of warm water. If the swelling is soft, it should be punc- 

 tured at the lowest point, and afterwards the cavity should be 

 syringed with Lugol's solution. If the tumor is hard and non- 

 fluctuating, a mercurial blister might cause absorption and at the 



