1S4 DISEASES OF THE SKIN. 



SiAfRCO^TIC MAJ^GE. 



The saicoptio mange is an artificial eczema oocasioned in the dog by 

 two exciting causes; one the irritation of an insect infesting the sldn 

 ( Sarcoptes Canis) ; the other the scratching of the animal in oonsequenoe 

 of its presence. 



Tl^s insect, the Acams, an animal parasite, is maintained hy the nour- 

 ishment it draws from the skin. The male acams is much the smaller, 

 remains in short burrows or vesicles, while the female tunnels the skin in 

 long canals. The ooulse of the latteris to seek a furrow on the surface, then 

 to attach itself, and by means of its jaws peneti'ate the outer skin or 

 cuticle, until it reaches the deeper and softer layers where it finds its nour- 

 ishment. It continues to burrow, laying one egg after another and 

 blocking up the passage with them. A young aoarua is developed from 

 the egg in about two weeks, and the number of eggs one insect lays is 

 near fifty. This production goes on continuously until the female dies, 

 which is generally in three or four months. 



The young aoari as soon as developed scamper over the sm'face, bore 

 quickly beneath, and occasion the most Intolerable itching. Around the 

 furrows form first small pimples, which change to vesicles and pustules ; 

 from them, bloody matter exudes, which dries and produces thick, dark 

 ci*usts. 



The itching caused by the insects on the surface of the superficial layers 

 of the skin incites scratching; the furrows are then opened and the acari 

 set free. The original eruption is destroyed, but eczema displaces it, 

 accompanied by the itching and irritation which invariably attends It; 

 then the disease increases in extent and intensity as it progresses. 



Diagnosis. —By a careful study of the eruption a diagnosis ought easily 

 to be reached, and less difficulty will be experienced in the earlier than in 

 the later stages. The condition of the animal and manner of attack will 

 weigh somewhat, as eczema more commonly occurs in debilitated sub- 

 jects. If other dogs in the same kennel are similarly aflTected, it would 

 suggest contagion. 



Vesicles in sarooptic mange predominate over any other form of erup- 

 tion at first; they occur alone and are not grouped together as in eczema; 

 again tbey are pointed, not flat or rounded like those of the last named 

 disease. 



After eczema has been produced by scratching, the difficulty of diagnosis 

 is Increased, but only slightly so, for new vesicles will constantly appear 

 on previously unaffected skin. 



Treatment. — While the exciting cause of sarcoptic mange is acari, 

 uncJeanliness oei-tainly exerts a predisposing influence, and this fact 



