OR INSECT OF ITCH AND MANGE. 
439 
oxen had any power to produce mange in horses, asses, or dogs, 
although they had bored through the skin in the space of thirty 
hours. Gohier maintains* that they appear to be destroyed 
when there. 
The acari of the sheep were (as has already been stated ) first 
discovered by Walz, and he very accurately described and deli¬ 
neated all their peculiarities. 
The sheep acari are generally about the same size as those of 
the horse. When examined with a naked eye, they appear to be 
whiter than the horse acari, and this difference is also seen when 
they are placed under a microscope, although in a less degree. 
The body of the male insect is more rounded, and that of the 
female more oval, than in the horse; but, on the whole, there is a 
very great resemblance between them. 
The time which the females require after pairing to produce 
their young, appears, according to my observations, to be from 
ten to twelve days. Walz states it to be sixteen days. 
I have never known or heard of any instance of the sheep acari 
having produced disease in the human being; nor on horses, 
cows, goats, or dogs. Vilborg, however, asserts^, that the calf 
of a healthy cow, that had never been near mangy cattle, nor 
exposed to any other means of infection, caught the mange by 
lying in a sheep-pen, in which some sheep had been that were in 
a very diseased state. He also says, that he has known cows to 
be infected by mangy goats and sheep. 
Gohier has found acari on dogs, cats, and rabbits ; and Bose, 
on cats. The former says that he could discover no visible 
difference between these insects and those taken from the horse, 
except that the former were rather smaller; and when taken from 
the body whence they derived their natural nourishment, they 
very soon died. Those taken from cats never lived beyond the 
third or fourth day. 
Bose has given delineations of the acari of the catj, but has 
not described them. They appear, according to these engravings, 
to be shaped like a turtle; and more resemble the acari of the 
human being than those of the horse. They are, however, con¬ 
siderably less, and have no suckers on their feet. The suckers, 
however, are not depicted in an engraving of the horse acari, 
also given by Bose: therefore it is doubtful whether this differ¬ 
ence really does exist, or it is only an error of the artist. 1 be¬ 
lieve, that if the suckers had been wanting, Gohier would have 
made mention of it. 
• Annales dc I’Agriciilture FraiKj. torn. Ixiv, 1815, p,21, 
t V^eterlnar. Sclskabets Skrifter. 1). ii, s. H.9. 
I Diet, dcs Scicnc. Medical, tom. xvii, PI. 3, Fig. 5. 
