MITES OF LOWER ANIMALS. 



55 



Besides the species of mite just described, a second species has 

 occurred, according to Hering, in the Fig 3 



gangrenous sores of the hoof of a 

 horse, namely, Sarcoptes hippopodus 

 (fig. 3). Hering says of it, that its 

 body is twice as long as broad, beset all 

 over with small hairs, like satin ; head 

 retractile ; proboscis consisting of two 

 valves moving laterally ; mouth di- 

 rected rather downwards; close to it 

 two small palpi; feet eight, five-jointed, 

 the last joint as long as the four pre- 

 ceding, with a small sucking disc at 

 the end, and two small hairs on each 

 joint. Two pairs of the feet originate 

 near the head, and two posteriorly on 

 the belly. On the abdomen a small 

 prominence, and four long, straight, 

 plumose bristles; their length 0-16, 

 their breadth 0-08 O085'". The 

 three pairs of bristles on the back, and those at the abdomen, 

 can be raised like the tail of a peacock. The large bristles are 

 plumose ; the hairs on the joints of the feet diminish in length 

 towards the extremity of the foot. Only the third joint of the 

 first pair of feet has a longer hair. 



On the human subject this form has not yet been detected 

 with certainty, but Hering thinks it has some similarity with the 

 Acarus favorum of Hermann. A peculiar mite was also found in 

 sores of the foot of a horse. 



4. That the Sarcoptes Bovis first observed by Gohier upon 

 Hungarian oxen in the last French war, also passes over to man 

 has long been doubted, until Thudichum recently described such 

 cases with certainty. 



A peasant believed he had transferred the mite to his upper 

 lip from the cattle treated with ointment, by incautiously scratch- 

 ing under his nose. On the upper lip were produced coalescent, 

 dark-red scales, vesicles, knots, and pustules elevated above the 

 skin, of various sizes, but of uniform hardness, which made their 

 appearance suddenly in the vicinity, and at last occupied the 

 whole lower part of the face, including the throat. The vesicles, 

 which were filled with white serum, sat upon a hard, red base ; 



