330 DISEASES OP CATTLE. 



same time prevent further injury to the part by making it more 

 painful, thus sparing it. 



Serous cysts. — These swellings are another variety of extravasation 

 cysts, and are due to such injuries as butting, running against hard 

 objects, and shipping bruises, which are followed by an outpouring 

 of blood and lymph into the tissue spaces. These cysts develop 

 rapidly and may reach the size of a man's head or even larger. They 

 are soft, edematous, and hot at first and contain a serous or blood- 

 tinged fluid. Later partially organized clots and shreds of a fibrin- 

 ous nature and of a gelatinous consistence are formed within, and 

 the temperature of the swelling is reduced. They appear on the sur- 

 face of the body, especially on the belly and flank of cattle. 



Treatment of serous cysts. — Treatment consists in opening the cyst 

 at the most dependent point with a sharp knife. The cavity should 

 be injected out twice daily with a 5 per cent solution of carbolic acid 

 and drainage encouraged by keeping the incision open. 



DERMOID CYSTS. 



These cysts have a wall which is almost an exact duplicate of the 

 structure of the skin, and frequently contain epidermal structures, 

 such as hair and teeth, which^ in the development of the embryo, have 

 been misplaced. Thus we may find in an ovary or testicle a dermoid 

 cyst, containing a tooth or a ball of hair. Dental cysts are included 

 in the above class. 



Dental cysts. — It occasionally happens that the teeth of cattle, in- 

 stead of developing normally within strong supporting alveolae, re- 

 main inclosed within a cystic membrane, which assumes a tumor-like 

 character. One tooth may be included alone in the cyst or a number 

 may be inclosed together. However this may be, the malformation 

 progresses, especially if confined to the incisor teeth, until the remain- 

 ing teeth, that began to develop normally, are crowded out of posi- 

 tion and rendered useless. The tumor may reach the size of a man's 

 fist. It appears to be fleshy and dents upon pressure, but it may also 

 appear on closer examination as though it contained irregular' sec- 

 tions of thin bone. The outer surface is always smooth, and no 

 indication of purulence, softening, or scab formation is ever exhibited. 

 Upon being laid open with the knife the tumor is seen to be sur- 

 rounded by a firm, smooth membrane which limits it completely 

 from the adjoining tissues. It is filled with material which possesses 

 partly edematous, partly fleshy, and partly bony properties. It is 

 supposed that this mass is composed of rudiments of the jawbone or 

 of the alveolar walls which, becoming spongy, lose themselves in the 

 soft, fleshy mass contained within the capsule of the tumor. It oc- 

 casionally happens that the tumor is hollow and that the cavity 



