[ 21 * 3 
The lower jaw of the pelican is aifo furnifhed 
with air; but by what means I do not know. 
Having formerly obferved thefe fa£ls, I made 
feveral experiments in the year 1758, upon the 
breathing of birds, to prove the free communica- 
tion between the lungs and the abovementioned 
parts. 
The firft was upon a cock. I made an opening 
into the belly of this animal, and introduced a 
lilver cannula ; then tied up the trachea , and found 
that he breathed by this opening, and lived ; but 
an inflammation came on, in the bowels, which pro- 
duced adhefions, and cut off the communication. 
I cut the wing through the os humeri y in another 
fowl, and tied up the trachea as in the cock ; and 
found that the air paffed to and from the lungs by 
the canal in this bone ; the fame experiment was 
made with the os femoris of a young hawk, which, 
was attended with nearly the like fuccefs ; but the 
paffage of air, through both thefe parts, efpecially 
the laft, was attended with more difficulty than in 
the firft experiment ; indeed fo much, as to render 
it impoffible for the animal to live longer, than to 
prove evidently, that he did breathe through the cut 
bone. 
The exceeding fingularity of thefe communica- 
tions, in birds, put me upon thinking, what could 
be the final caufe. At firft I fufpe&ed, that it might 
be intended for the benefit of flying, that being the 
circumftance which appears the moft peculiar to 
birds ; and it might be of fervice in this refpe£l, I 
thought, by encreafing the volume and ftrength, 
with the fame quantity of matter, and therefore 
E e 2 without 
