of Animal Subflances. 331 
In the fame collection I faw an aftragalus, (one 
of the bones of the foot) which had come away 
entire, and the patient, as Mr- Fyfe informed 
me, had the perfeCl ufe of his foot and ancle. 
I likewife faw in the fame place, a thigh bone, 
which had been broken, the ends had not co- 
aptated, but had overfhot each other three inches, 
and were perfectly united- Cafes of this fort 
I have often feen, and have now a thigh bone 
by me, united in the fame manner; but in 
that bone in the poffeflion of Dr. Monro, there 
is this circumftance, which I had never before 
obferved, (hat the fides of the bone had not 
approximated each other, but in one point. 
The callus had fhot out in fuch a manner as to 
form cancelli, and the void fpace had all the 
appearance of having contained a medullary fub- 
ftance. Dr. Monro told me he had a whole chefl: 
of regenerated bones in his poffeflion. He like¬ 
wife deferibed to me the following experiment, 
he had made. 
He laid open the abdomen of a pig for feveral 
inches, in fuch a manner, that the inteftines 
protruded; which convinced him, that all the 
integuments were completely divided. He then 
reduced the inteflines, and fewed up the wound. 
After it was perfectly united, he killed the pig. 
He then made incifions above and below, and on 
one fide of the cicatrix ; after which, he injefted 
the aorta; and, though there was not a poflibility 
