268 PRINCIPLES OF VETERINARY SCIENCE 



cation of blindness. A cheap and most satisfactory eye wash 

 for animals is made by dissolving a level tablespoon of common 

 table salt in two quarts of freshly boiled water. It is easily 

 applied by means of an eye dropper. 



DEAFNESS 



This is neither a common nor a very serious affliction of animals. 

 A deaf horse is a nuisance from the driver's viewpoint, but is 

 capable of giving good service. There is little that can be done 

 in the way of medical treatment for deafness. When it is caused 

 by pressure from an ear cyst, a surgical operation to evacuate the 

 contents of the cyst would be likely to remedy the condition. 



TUMORS 



Tumors are new growths which appear at times in various 

 tissues of the body from no apparent cause. They may be either 

 benign and slow in development, or malignant and spread very 

 rapidly. Benign tumors remain localized and are not dangerous 

 unless vital organs are involved. Warts are benign tumors. 

 They occur on the thin parts of the skin. To remove warts pull 

 or twist them off, cut them away with a knife, or burn them with a 

 hot iron. All malignant tumors should be excised completely 

 and early with the surgeon's knife, in order to prevent them from 

 encroaching upon neighboring tissues and spreading to other 

 parts of the body. As a rule, caustic agents are to be employed 

 to destroy tumors only on expert advice, for they tend to cause 

 them to spread and favor their growth. 



A common form of malignant tumor, occurring in white and 

 gray horses, is known as melanosarcoma and the condition pro- 

 duced as melanosis. Such a tumor is always black in color and 

 contains a large amount of melanin, the pigment found in the 

 skin. 



CANCERS 



Cancers are malignant tumors composed of epithelial and con- 

 nective tissues. They have a tendency to persist and grow 

 down into the surrounding tissues. They are found either on 

 the surface epithelium or in the epithelial cells of glands. The 



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