422 Dr. Crawford’s Experiments on the Matte) 
The mufcular fibres of animals contain fixed and phiogiln- 
cated air, the inflammable principle in the ftate of heavy and 
of light inflammable air, and a fubflance which, by means or 
heat or of putrefaction, is capable of being converted into 
animal hepatic air*. When the mufcular fibre, after the 
death of the animal, is expofed to the pure air of the atmo- 
fphere; the latter, by a fuperior attraction, combining with the 
heavy inflammable air, produces fixed air, and at the lame time 
furnilhes' the quantity of heat necefl'ary to the formation ot 
animal hepatic air. The cohefion of the fibre being thus de- 
frayed, the fixed, as well as the light inflammable and phlo- 
gifticated air, which enter into its compofition, are difengaged, 
and the two latter fluids uniting with each other produce the 
volatile alkali. _ _ . 
The alterations which take place in putrefaction are in molt 
refpeCts fimilar to thofe which arife from deftruthve diftilla- 
tion. By expofure to heat the fixed air of the animal fibre is 
extricated, hepatic air and volatile alkali are produced, and the 
inflammable principle not coming into contaCt with the pure 
' air of the atmofphere, is raifed in the form of heavy inflam- 
mable air. ... * 
1 have found, that the fetid odour of animal hepatic air is 
defrayed by mixing it with pure air, and fullering it to i^.main 
in contadt with that fluid for feveral weeks. ^ hen it was 
placed in this fituation, it acquired an odour which was not 
exactly fimilar to any that I had ever before perceived, but 
which bore feme refemblance to that of inflammable air ob- 
tained by diflolving iron in fpirit of vitriol. 
* It is fcarcely neceffary to obferve, that the exiftence of fixed, inflammable, 
and phlogifticated air in animal fubftances, and the eompofition of volatile alka >, 
were difeovered before I began to give particular attention to this fubjedh ^ 
