of Cancer , and on Animal Hepatic Air . 40 1 
Priestley’s teft to be as pure as common air; and it was 
evident, that the aqueous vapour which came over in the mid- 
dle of the procefs was not mixed with any permanently 
elaftic fluid ; becaufe, when this vapour was received in an in- 
verted bottle filled with mercury, it was condenfed into wa- 
ter, without any admixture of air. Indeed, if the odoriferous 
principle in the matter of cancer confift of volatile alkali com- 
bined with animal hepatic air, it could not be expedted that 
it lliould acquire a permanently elaftic form by iimple expofure 
to heat ; becaufe when alkaline and animal hepatic air unite 
together, they form a non-elaftic fubftance that condenfes upon 
the inner furface of the veflel in which they are mixed. 
To difcover whether other animal fubftances yield an aerial 
fluid, fimilar to that which was extricated in the foregoing ex- 
periment from the matter of cancer by means of heat, a portion 
of the fiefh of the neck of a chicken was introduced into a fmail 
coated glafs retort, which was gradually expofed to heat in a fand 
bath till it became red-hot. A thin phlegm, of ay ellowifh colour, 
firft came over : this was foon fucceeded by a yellow empyreu- 
matic oil, and at the fame time a permanently elaftic fluid, having 
an odour refembling that of burned feathers, began to be difen- 
gaged. A flip of paper, tinged with litmus and reddened by ace- 
tous acid, being held over this fluid, became blue. The neck of 
the retort was now introduced below an inverted jar filled with 
mercury, and a confiderable quantity of air, together with a fetid 
empyreumatic oil, were received in the jar. This air was highly 
inflammable : it had a very fetid odour. When a bottle, con- 
taining a portion of it, was agitated with diftilled water, nearly 
one-half of it was abforbed. The refidue was inflammable, and 
burned firft with a flight explofion, and afterwards with a blue 
lambent flame. A little nitrated lilver being dropped into the 
Vol. LXXX. G g g water 
