172 C H- E M I 
raid carbon, refpiration muft nece (Tardy augment the pro- 
portion of azot. The ltudy of the mechanilm of the other 
functions, which remains to be purfued, will undoubt¬ 
edly lead to' new difcoveries, itill more important than 
the preceding : what has been performed within a few 
years, naturally prompts us to imagine, that ftilj more 
will be done. The analogy of aCtion which has been 
diicovered between digeltion, refpiration, circulation, 
and infenfible perfpiration, has begun to eftablifh on new 
views, more lolid than were heretofore pofTelTed, a fyftem 
of animal phyfics, which promifes an abundant harveft 
of dilcoveries and improvements. Unqueltionably it will 
be in purfuing the phenomena of digeltion and growth 
in young animals, that an edifice equally novel and folid 
will be ereCted on thefe foundations. Every thing is 
ready for this grand work; feveral philofophers purine 
this unbeaten path of experience; frefh ardour, fpring- 
ing from thefe new conceptions, animates thofe.who are 
engaged in this branch of phyfics; and the track they 
have juft begun to explore, appears fuch as mult lead 
them to more precife and accurate refults, than any that 
have hitherto been advanced on the functions which con- 
llitute animal life. The advantages, therefore, to be de¬ 
rived from a due contemplation of thefe matters, will be 
found in our acquiring a fuperior knowledge of the func¬ 
tions of the animal economy, particularly refpiration ; 
digeltion ; hematofis, or fanguification j infenfible per- 
ipiration ; the fecretion of the bile ; ofiification and of- 
teogony; nutrition; the difeafes dependent on the de¬ 
generation of the humours, &c. animal concretions; 
the aCtion of various medicines on the humours, &c. 
the arts employed in the manufacturing of animal mat¬ 
ters, particularly thole of the tanner, currier, preparers 
of different kinds of glue and fize, makers of catgut, 
jrliofe who extra# oils, and thole who work on horn, 
bone, tortoifelhell, &c. 
THE SPONTANEOUS DESTRUCTION OF VEGETABLE 
AND ANIMAL SUBSTANCES. 
When vegetables and animals are deprived of life, or 
when their products are removed from the individuals 
of which they made a part, movements are excited in 
them, which deltroy their texture, and alter their com¬ 
pofition. Thefe movements conllitute the different kinds 
of fermentation. The intention of nature in exciting 
them is evidently, to render more fimple the compounds 
formed by vegetation and animalization, and to caufe 
them to enter into new combinations of different kinds. 
When a portion of matter has been employed for fome 
time in the fabrication of an animal or vegetable body, it 
muff be rendered up by it to'form new compofitions, as 
Icon as the functions of the body are at an end. From the 
general definition of fermentation, it would feem that there 
ought to be as many - peculiar and different fermenta- 
.tions, as there are vegetable and animal matters to be 
changed and decompoled : but feveral of them purfuing 
a fimilar path to arrive at a more fimple ftate of compo- 
fition, the number of fermentations lias been reduced to 
three, the vinous, acetous, and putrid. 
Vinous fermentation, as its name imports, is that which 
produces wine or alcohol. The faccharine matter is the 
only one which undergoes this fermentation, when di¬ 
luted with a certain quantity of water, and mingled with 
a third lubftance of fome kind, vegetable or animal, as 
extraCt, fait, fecula, or the like: for it is now fully 
proved, that fugar and water alone never enter into vi¬ 
nous fermentation. The faccharine matter is fo abun¬ 
dant and generally diffufed through vegetable and even 
animal fubftances, that there are a great number of bo¬ 
dies capable of affording wine, or yielding alcohol. All 
fweet and faccharine fruits reduced to a pulp, and more 
efpecially their expreffed juices, undergo a movement, 
when they are at a temperature of 62° or upwards, if 
they be in a large body, and particularly when neither 
£00 thick nor too thin. Hence the great number of dif- 
S T R Y. 
ferent wines, comprehending the decoCfions of grain 
malted, and by this procefs converted in part into fac¬ 
charine matter, and even the vinous liquors made with 
jnilk, honey, blood, See. Vinous fermentation announces 
itfelf in faccharine liquors by an increafe of volume, the 
formation of a copious feum. which covers t'heir furface, 
rife of temperature, the difengagement of a confiderable 
quantity of carbonic acid gas, and the converfion of a 
fweet fluid into a (harp, warm, and pungent, liquor. 
The caufe of this fermentation appears to be owing to a 
decomposition of water, a great part of the oxygen of 
winch, attacking the carbon of the fugar, burns it, and 
converts it into carbonic acid. At the fame time the 
hydrogen of the water attacks .the fugar diverted of its 
carbon, and, combining with it, gives birth to alcohol. 
Thus alcohol may be defined to be fugar minus a cer¬ 
tain quantity of carbon, and plus a certain portion of 
hydrogen. This theory explains both the formation of 
the carbonic acid evolved during the progrefs of vinous 
fermentation, and that of the alcohol, as well as all the 
properties of this new production. 
Pure alcohol is a white liquid, of a ftrong fmell, of a 
hot and acrid tafte ; rifing in vapour at a temperature of 
150°; inflammable at any temperature; affording much 
water and carbonic acid in burning ; yielding no fmoke 
in combuftion; mifcible with water in any proportion, 
and expelling its air and a part of its caloric while com¬ 
bining with it; diffolving pure or cauftic alkalis; de- 
compofing acids, and convertible into ether by this de- 
compofition ; diffolving deliquefeent neutral halts, and 
feveral metallic ones ; taking from vegetables their vo¬ 
latile oil, aroma, refill, balfam, part of their gum-refin, 
and many colouring matters ; and of great ufe in various 
procefles of the arts, in confequence of thefe feveral pro¬ 
perties. The reader may have already remarked, that 
the formation of alcohol takes place at the expence of 
the deftruClion of a vegetable principle, and that the 
faccharine matter undergoes a decompofition, which re¬ 
duces it to a more fimple term ; thus vinous or fpiritous 
fermentation is a commencement of the deftruction of 
principles formed by vegetation : and hence it may be 
regarded as one of the movements eftablifhed by nature, 
to Amplify the order of compofition, which vegetable 
fubftances exhibit. 
The acid or acetous fermentation is the fecond natu¬ 
ral movement, which contributes to reduce vegetable 
compounds to more fimple ftates of compofition. This 
fermentation, which produces vinegar, takes place only 
in liquors that have previoufly undergone the vinous 
fermentation. It has been obferved, that the contact of 
air is neceffary to the production of vinegar: it has even 
been perceived, that wine in tunning four abforbs air; 
fo that a certain portion of the oxygen of the atmofphere 
appears to be neceffary to the formation of the acetous 
acid. Unqueftionably there are feveral other fermenta¬ 
tions analogous to that which forms vinegar, though 
their products are not yet well known ; Inch, for in- 
ftance, are that of water mixed with ftarch, called ftarch- - 
makers four water, and thole which form four bread, 
four kraut, and four liquors. All thefe changes are to 
be confidered as means of decompofition for Amplifying 
the complex combinations of vegetables. 
Finally, after vegetable liquors, or their folid parts 
moillened, have paffed to the acid ftate, their decompo¬ 
fition, continuing under favourable circumffances, name¬ 
ly, a gentle or warm temperature, expofure to air, and 
the contact of water, leads them into putrefaction, which 
terminates in volatilizing moft of their principles under 
the form of gas. Water, carbonic acid, carbonated, and 
even fulphurated, hydrogen gas, volatile oil in vapour, 
and fometimes even azotic gas and ammoniac, are evolv¬ 
ed; and after this there remains nothing but a brown or 
black refiduum known by the name of mould, formed of 
carbon fomewhat fat and oily, from which water Hill ex¬ 
tracts feme faline fubftances and a little extractive matter. 
Nature, 
