DISEASES OF THE SKIN. 291 



ECTHEMA. 



This condition is an eruptive pustular disease. It is said to be 

 contagious. It is sometimes called the American skin disease of 

 horses. 



It is characterized by medium sized, hard pustules over the 

 body. These pustules finally burst, and discharge a thin, sticky 

 fluid of the color of straw. Finally an unhealthy-looking scab 

 forms, which drops off in time, leaving a cicatrice. 



Treatment. — Give six drachms of aloes, and follow with 

 potassium nitrate, one-half ounce; sweet spirits of nitre, one 

 ounce. Several doses of the latter may be given. Locally the 

 carbolic acid lotion should be used. The different other prepara- 

 tions referred to under the head t^f skin disease may be used. 



MANGE. 



This disease is also called scabies. It is due to an animal para- 

 site belonging to the family of sarcoptes. They burrow in the 

 flesh, and occur in the horse, man, sheep, pigs, and cattle. Be- 

 sides the sarcoptes, there is a parasite known as the dermato- 

 dectes. They simply hold on to and prick the skin. Another 

 variety is known as symbrotes; they neither burrow nor prick 

 the skin, but cause considerable irritation, and are common to 

 the horse and ox. The above mentioned parasites are those 

 causing mange, although of the three varieties named the sar- 

 coptes is probably the one oftenest met with in mange. They 

 may be carried from one animal to another by means of the har- 

 ness, saddle, or clothing. The disease is not frequently met with 

 on the American Continent, and the parasites causing mange are 

 not spontaneously generated. At the same time, it should be 

 remembered that dirty and badly kept animals are more prone to 

 receive the parasites, and offer better advantages for their pro- 

 duction. 



Symptoms. — If sarcoptes be present there will be vesicular 

 eruptions and intense itching, which increases towards night. 



