306 DISEASES OF CATTLE. 



B. — Cysts. 



I. — Cysts which develop in preexisting cavities. 



1 Retention cysts. 



2 Proliferation cysts. 



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



1 Dermoid cysts. 



III. — Cysts tchicli originate independently as the resnlt of pathological changes 



and are nofitumorous. 



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 fieshlike appear- 

 ance of the one and the crablike proliferations of the other — ^namely, 

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



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

 history and (2) examination of the tumor. 



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

 the tumor and its rapidity of growth 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. While 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 of 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. 



