320 DISEASES OF CATTLE. 



B. Cysts. 



I. — Cysts which develop in preexisting ca>viti€s. 



1 Retention cysts. 



2 Proliferation cysts. 



II. — Cysts which are of congenital origin and are true tumors. 

 1 Dermoid cysts. 



III. — Cysts which originate independently as the result of pathological changes 

 and are nontumorous. 



1. Cysts formed by the softening and disintegration of lesions Softening cysts. 



2. Cysts formed around parasites Parasitic cysts. 



3. Cysts formed by an outpouring of blood and lymph into the tissue spaces with 



subsequent encapsulation of the fluid Extravasation cysts. 



Terminology. — The principle of naming tumors is quite simple. 

 The Greek word "oma" (plural "omata") means tumor. This word 

 " oma " is added to the stem of the word ordinarily used to designate 

 the kind of tissue of which the tumor is composed. Thus a tumor 

 formed after the type of fibrous tissue is a fibroma. The only excep- 

 tion to this is in the naming of the two large classes of malignant 

 neoplasms. There the names were formed from the flesh-like appear- 

 ance of the one and the crab-like proliferations of the other — namely, 

 Sarcoma (sarks=flesh), carcinoma (karkinos=crab). 



Diagnosis. — In the diagnosis of tumors note is taken of (1) clinical 

 history and (2) examination of the tumor. 



(1) Clinical history. — Circumstances connected with the origin of 

 the tumor and its rapidity of grow th may point to an inflammatory 

 swelling rather than a tumor. The location of the tumor at its com- 

 mencement is important, as, for instance, in diagnosing between 

 lipoma and carcinoma, the former being more or less movable under 

 the skin, while a carcinoma develops in the skin. TMiile tenderness 

 on pressure may be caused by compression of a sensitive nerve by a 

 tumor or by tumors of the nerve or nerve sheaths, as a rule this 

 symptom is indicative of inflammatory swelling rather than the 

 existence of a tumor. 



(2) Direct examination of the tumor. — In the application of this 

 diagnosis the trained observer will note color, size, shape, and surface 

 structure, transmission of light, movableness, consistence, resistance, 

 pulsation, and crepitation. Percussion, auscultation, and exploration 

 are also available methods. Finally, microscopic examination of the 

 growing portions of the tumor by a pathologist will be found most 

 satisfactory. 



GENERAL TREATMENT OF TUMORS, 



For benign tumors treatment is required only when it damages the 

 animal's value or when merely for sake of appearance. When it is 

 possible, the removal of the tumor by an operation is indicated. If 



