3IO ARACHNOIDEA. 



CASE This species occurs most frequently on the horse and sheep ; 

 but it is also found on the ox. It is also said sometimes to stray 

 to man ; but this is an error. We read, indeed, in Hering, of two 

 cases where the itch was transferred from diseased horses to men, 

 and others are cited elsewhere ; but as the insect was not 

 identified, and the symptoms do not correspond with those 

 produced by the Psoroptes equi, it is most probable that the 

 horse was only suffering from an attack of Sarcoptes scabiei, 

 and communicated it back again to the class from which it 

 received it. 



Still the cases are instructive, therefore we quote them. The 

 first case is taken from the Italian journals :• — 



" In January, 1820, a farmer, Magni, bought a mangy horse at 

 the market in Bergamo (in the province of Mailand), on which he 

 rode home. The morning after his arrival he felt a strong itch 

 over almost the whole body, as also his son and a friend, who 

 had accompanied him from the market. The stable-boy, who 

 had to attend to the horse, scratched himself very much the 

 following day, as well as another who had worked some hours in 

 the field with him. At last more than thirty persons on the 

 farm had the itch, as well as some horses, all directly or indirectly 

 from this horse. Magni sold the animal to a joiner, who was 

 soon attacked; not less so his boy, who had laid his hand on 

 the horse's back, and a cow that had rubbed against the collar 

 and crib of the horse. It is noticeable that all the individuals 

 who were attacked felt the itch in twenty-four or thirty- six hours 

 after coming in contact with it; this is the more remarkable as it 

 was in January. The itch character of the sores is confirmed by 

 credible physicians and surgeons." 



The second instance is related by Sydow, and is to the 

 following effect : — 



"In the summer of 1808 we had a horse in our Animal 

 Hospital suffering from the so-called Grecian Mange, which is a 

 very obstinate disease, and defies the best medical treatment. 



