44 PROGRESS OF VETERINARY SCIENCE AND ART. 
both, suffer. They are generally caused by horses slipping 
back in trotting, or dragging loads along a slippery pavement, 
or in the stall as the animal is rising. We find in these 
instances laceration of the tendon of the gluteus externus, and 
even partial or complete fracture of the trochanter minor. 
Besides having seen a very marked case during life, I have 
drawn three femurs from specimens in different museums 
indicating similar lesions. 
THE ACARI OF SCABIES IN MAN AND ANIMALS. 
“The contagion of Scabies (Mange, Itch) from 
Animals to Man.” — According to Bourguignon the con- 
tagion of scabies from animals to man was held as incon- 
testable, before he himself and Delafond proved the contrary. 
All diseases of the skin of animals were held as mange. And 
although Gohier, Rose, Hertwig, Yiborg, and others, cite 
examples of man having contracted the disease from brutes, 
it had not been scientifically demonstrated in these, hence it 
could not be irrefutably proved as occurring in man by con- 
tagion. The acarus of the dog was unknown till November, 
1854, when M. Delafond discovered it, and still most of the 
diseases of the skin of this animal were considered of the 
nature of psora and transmissible to man. 
To avoid all sources of fallacy, Bourguignon considers no 
case of transmission of scabies, from animals to man proved, 
unless the same acarus is discovered in both, and unless all 
the symptoms of itch in man are discoverable. The acarus 
of the horse may produce transient phenomena when placed 
on the skin of man, but the acarus equi dies shortly after 
changing abode ; hence if men attending on mangy horses 
suffer from prurigo, if they keep away from the diseased ani- 
mals a few days, all the symptoms will disappear without 
specific treatment, proving that they are kept up by a conti- 
nuance of the cause, new acari passing over the skin con- 
stantly, but not taking up a permanent abode or procreating. 
Bourguignon at first believed, as every one else, in the con- 
tagion of scabies between animals of different species. Never- 
theless, patients having presented themselves at the hospital 
of Saint Louis as affected with the mange of the cat, dog, or 
horse, without that Bourguignon could discover any other 
than the acari of man, doubts arose in his mind, and he began 
to experiment. He placed on his skin acari of the horse ; he 
w T as pricked by them, suffered from itching, but nothing 
further. He concluded that the transmission could not be 
effected. The acari of man, placed on dogs, cats, rabbits, 
