of Cancer, and on Animal Hepatic Air . • 4 a 3 
The pure air was previoufiy agitated with lime-water to free 
it from fixed air, and a portion of the hepatic air, having been 
likewife agitated with lime-water, was found not to occafion 
any precipitation in that fluid. The airs were reduced by the 
explofion to one-fourth of their original bulk. The refidue 
was then transferred over mercury into a (lender graduated 
tube, and diftilled water being admitted, eight-tenths w r ere 
abforbed. To a portion of this water, when filtered, variolated 
filver was added, which inftantly occafioned a copious precipi- 
tate. To a fecond portion was added muriated barytes, which 
occafioned a flight white precipitate not re-diflblvable in a large 
quantity of water; lime-water being added to a third portion, 
did not produce any fenfible precipitation. From the laft fadl 
it does not follow, that no fixed air exifted in the refidue, be- 
caufe the marine acid, which it evidently contained, would 
diffolve the calcareous earth of the lime-water. As a great 
diminution, however, refulted from the combuftion ; and as it 
appeared, from chemical tefts, that the refidue w r as moftly com- 
pofed of marine and vitriolic acid airs, it is manifeft, that, if 
any fixed air was produced, its quantity mu ft have been very 
inconfiderable. 
It has been already obferved, that a flight precipitation took 
place upon the addition of the muriated barytes. The precipi- 
tate was much more confide r able when, mpon repeating the 
experiment, the refidue after the explofion was not tranfi- 
ferred into a graduated tube previoufiy to the admifiion of the 
diftilled water; but the latter was immediately introduced into 
the veflfcl in which the airs were fired. The reafon of this 
difference is evident. The flight, precipitate by . the muriated 
barytes, in the firft inftatice, depended upon the exiftence-of a 
fmall quantity; of variolic acid in an aerial form, or in the 
flats 
