244 Diseases of the Genital Orga?is 



On the other hand, the occurrence in geldings has been rela- 

 tively common. This may be apparent only. Since in 

 America essentially all colts not desired for breeding pur- 

 poses are castrated, the ratio of stallions to geldings is less 

 than five per cent. Consequently one would logically expect 

 to see at least twenty to twenty-five malignant new-growths 

 in geldings to one in stallions. The malignant tumors of 

 these parts may be sarcomatous but are most frequently 

 carcinomatous. Their character is generally diagnosable 

 by clinical examination. Usually there is abundant necro- 

 sis of the diseased parts and rapid growth and in all re- 

 spects they show typical malignancy. As in malignant dis- 

 ease generally, there is rarely any early trace of cancer 

 cachexy. The general health of the animal remains as a 

 rule unimpaired for several months, unless the disease in- 

 terferes with some vital function either by mechanical im- 

 pediment or by invading a vital organ (liver, lungs). Ma- 

 lignant disease of the penis, sheath, and prepuce ordinarily 

 proves fatal indirectly, through daughter tumors in a vital 

 organ. Thus, in one case in my clinic, carcinoma of the 

 sheath caused death through the breaking down of a daugh- 

 ter tumor in the lungs. 



The clinician should not err in diagnosing benign tumors 

 of the penis as malign. The ordinary benign epithelioma 

 of the equine penis is highly vascular and undergoes pres- 

 sure and attrition necrosis. The necrotic tissues and the 

 sebum produce much highly fetid pus containing tissue de- 

 bris, and often blood. That should not be accepted as evi- 

 dence of malignancy. The necrosis of malignant neoplasms 

 is fundamental and inherent, and not attributable to pres- 

 sure or attrition. When essential, the diagnosis may be 

 safeguarded by the removal of a portion of the tissue for 

 pathologic study. 



The veterinarian should also be on the alert in diagnosis 

 not to mistake bursattee of the penis and prepuce for ma- 

 lignant neoplasms. The necrosis of bursattee is funda- 

 mental, like cancer, but its other characters serve to differ- 



