122 DISEASES OF SHEEP. 



Under certain circumstances, produced by diseases, food, 

 etc., the wearing out of the teeth sometimes varies con- 

 siderably from the above order. Some sheep lose the crovms 

 of their teeth in the sixth and seventh years, while others 

 retain them unchanged until the eighth and tenth years or 

 even longer. Vigor and health of body preserve the teeth. 



CANCER OF THE TONGUE. 



Cancer of the tongue ia a species of gangrene or mortifi- 

 cation of the spleen, which is contagious, and may be rec- 

 ognized by a blister on the tongue, which speedily changes 

 to a cancerous ulcer. Symptoms of general sickness are 

 not usually observed before the appearance of the local 

 disease, but fever is sometimes present. The tongue, palate 

 and gums are swollen, bright red and warmer than usual. 

 The motion of the tongue is obstructed, and blisters of the 

 size of a pea or hazel-nut, filled with serum, blood or pus, 

 are found on it, which burst, discharge their contents and 

 leave gangrenous wounds or continue to spread. The blis- 

 ters are either few and large or many and small. The part 

 of the tongue on which the ulcers are situated is insensible, 

 cold and of a blue or black color. If the disease spread, 

 the larynx and pharynx are also attacked. After the 

 ulcers have developed, symptoms of fever appear, and if 

 nothing is done to check the disease, death results after 

 convulsions, distension of the belly, cold feet and cold 

 sweats, in twelve to forty-eight hours. Recovery may be 

 hoped for when a good treatment is adopted early to make 

 the ulcers assume a mild form. 



The disease frequently attacks horses and mules. In 

 1862, 1 treated more than thirty thousand horses and mules 



