452 



trichophyton, and is rationally treated by cutting off the hair and 

 applying tincture of iodine or a solution of corrosive sublimate (4 

 parts to 1,000 of water). 



Parasite: Aclwrwn ScMrdeini. Malady: Favus, Honeycomb 

 ringworm.— ^iegnin and Goyau, who describe this in the horse, say 

 that it loses its characteristic honeycomb or cup-shaped appearance, 

 and forms only a series of closely aggregated, dry, yellowish crusts the 

 size of hemp seed on the trunk, shoulders, flanks, or thighs. They are 

 accompanied by severe itching, especially at night. The cryptogam, 

 formed of spherical cells with a few filaments only, grows m the hair 

 follicles and on the cuticle, and thus a crust often forms around the 

 root of a hair. Like the other cryptogams, their color, as seen under 

 the microscope, is unaffected by acetic acid, alcohol, ether, or oil of 

 turpentine, while the cells are turned bluish by iodine. For treat- 

 ment, remove the hair and apply tincture of iodine or corrosive subli- 

 mate lotion, as advised under the last paragraph. 



Parasite: Microsporon Furfur. Malady: Parasitic pityriasis.— 

 This attacks the horse's head where the harness presses, and leads to 

 dropping of the hair, leaving bald patches covered with a branlike 

 scruff, without any eruption, heat, tenderness, swelling, or rigidity of 

 the skin. A lotion of carbolic acid, 1 dram, and water 2i ounces, is 

 usually applied to effect a cure. 



animal parasites of the skin. 



Acariasis: Jfcmr/e.— This affection is due to the irritation of the skin, 



caused by the presence of a nearly microscopic acarus or mite. The 



disease varies, however, according to the species of acarus which 



infests the skin, so that we must treat of several different kinds of 



acariasis. . . . m • • 



Parasite: Sarcoptes equi. Malady: Sarcoptic acariasis.— i His is 



the special sarcoptes of the horse, but under favorable conditions it 



can be transmitted to ass and mule, and even to man, and may live 



indefinitely on the human skin. The mite is nearly microscopical, 



but may be detected with a magnifying lens among moving scruff 



taken from the infected skin. Like all sarcoptes, it burrows little 



o-alleries in and beneath the scruff skin, where it hides and lays its 



eggs and where its young are hatched. It is therefore often difficult 



to find the parasite on the surface, unless the skin has been heated 



by a temporary exposure to the sun or in a warm room. Even then 



it may be needful to tie the scab on the human arm till a pricking is 



felt when the acarus will be found in the center of a minute papule 



caused by its bite. Like other acari, this is wonderfully prolific, a 



new o-eneration of fifteen individuals being possible every fifteen days, 



so thlt in three months the offspring of a single pair may produce a 



generation of 1,500,000 young. The sarcoptes have less vitality than 



the nonburrowing acari, as they die in an hour when kept in dry air 



