[)74: Acarus Mange. 



Biigge proves, wlio encountered the disease most frequently in 

 4 to 8-year-old animals, but sometimes also in younger animals 

 and only very rarely in older ones. With the exception of a 

 case in which Gros saw the disease on the muzzle of a cow, the 

 skin affection usually prefers the body, neck and shoulders 

 (Old, Grhnm, Biigge) ; it may, however, affect the whole surface 

 of the body (Biichli). In Biigge 's cases, in which many animals 

 were affected simultaneously, the hock joint was the central 

 point of the disease. On the skin one finds nodules of hazelnut 

 size, conical and closely crowded, hairless, and at times reddish 

 colored, from which purulent, cheesy masses with very many 

 mites may be expressed. Biigge also noticed moderate itching, 

 and in consequence the animals licked the diseased places. While 

 Old sometimes saw spontaneous healing, in other cases cure did 

 not always result even after suitable treatment. 



In the goat the hair sac mites occasion only quite excep- 

 tionally pea to hazelnut-sized reddish nodules, occurring prin- 

 cipally either on the body (Niederhausern, Nocard, Railliet), 

 or on the head and legs (Bach). Slight itching may also be 

 present. Healing does not result even after appropriate treat- 

 ment. 



In the horse Gros saw in one case reddening of the skin 

 around the nose, while Walther noticed in a horse intense itch- 

 ing on the left side of the root of the tail, and hairless, round 

 spots as large as a twenty-five-cent piece on wdiicli the swollen 

 skin was covered with sticky fluid oozing out like drops of sweat. 

 In Schenzles' cases the disease simulated, on the other hand, 

 alopecia areata, and started on the head at the bridge of the 

 nose, around the eyes, on the forehead, nape of the neck and 

 in the region of the parotid gland, with the occurrence of hair- 

 less spots as large as a fifty-cent piece, irregular in form and 

 with poorly defined boundaries. Subsequently the circum- 

 scril)ed loss of hair extended backwards to the shoulder region, 

 and finally spread over the whole body, after repeated rubbings 

 with carbolized glycerine. At this time fine scales appeared on 

 the otherwise healthy skin. Itching was absent up to the end 

 of the attack. 



Ill rabbits, Pfeififer observed acariasis in China. The affection 

 began with falling out of hair and scaling around the eyes, whence it 

 extended to the root of the ear and the external and internal surfaces of 

 the shells of the ear as well as on to the skull. In the meantime it caused 

 folds and thickening of the skin, scabs, copious secretion of purulent 

 material, as well as destruction of eyelids and ears, or it produced a 

 violent inflammation of the middle and internal ear, and now and then 

 occasioned even a fatal inflammation of the membranes of the brain; 

 the eyeballs remained uninjured except for a superficial keratitis. The 

 acarus mites found in the contents of the hair follicles were much smaller 

 than those of the dog. 



Diagnosis. The pustular form of acariasis produces a 

 rather characteristic form of the disease in dogs. The often 



