436 
ON THE ACAKUS. 
thus becomes inflamed, thickened, and hardened. When the 
acari remove from a mangy place, and the horse ceases to rub it, 
a new smooth, black scarf-skin is speedily formed. 
In the foregoing description of the changes in the skin I have 
described the mange in horses as I generally have seen it. I wish 
that 1 could give a clearer and more particular description of this 
disease; but it does not put on the same appearances in all 
horses that are affected by it; and I must candidly confess that 
frequently, when I have examined horses which have had some 
skin disease and have been unable to discover any acari, I have 
been in doubt whether it was really mange or not. 
The existence of the acari forms the only certain proof of the 
disease being mange. Hence veterinary surgeons and possessors 
of horses frequently err, as they invariably pronounce every 
itchy eruption of the skin to be mange. Happily the results of 
this error are not very bad, since the treatment which is found to 
be of service in scrophula and other skin diseases is also equally 
valuable in mange. 
The horse acari will be communicated to the human being, 
and also to other animals, and frequently occasion great disease 
of the skin : this however does not always occur, on account of 
the difference in the skin of different individuals. 
Instances of the horse acari being communicated to the human 
being have been recorded by many writers; namely, by E. Viborg, 
(Sammlung von Abhandlungen), by Sick (Unterricht fur die 
Landwirthe zur Abwendung und Heilung der in Kriegeizeiten vor 
kommenden Vichkrankheiten, Berlin, 1807), and by Greve (Er- 
fahrung und Beobachtungen liber die krankheiten der Haus- 
thiere, Oldenburg, 1818). The last writer also speaks of this 
disease being communicated from the horse to the ass, but main¬ 
tains that this is the case with no other of our domesticated 
quadrupeds. This assertion, however,is contradicted in the Revue 
Medic, tom. x, and also in Froriep’s Notizen. 1823, where it is 
said that in Bergamo several horses, thirty men, and a cow were 
infected by one mangy horse. 
Grognier, in the yearly report of the Veterinary school at Lyons 
for 1817 (Annal.de f Agricult. Franc. 1817), states that a mangy 
horse infected several men and two cows which were in stalls near 
him. I myself know a gentleman, near Berlin, whose horses were 
suffering under a very severe attack of mange. His sheep sud¬ 
denly, and without any apparent cause, became mangy ; and, at 
length, all the members of his family and his servants had an 
itchy eruption on every part. 
I also saw two grooms belonging to the veterinary school in 
this town who were twice tormented by an itchy eruption when 
