3?2 C H E M 
be increafed and continued upbn the calcined bones, they 
acquire a fulible property. If the fire be maintained to 
fucli a degree as to make the fufible matter of the bones 
red-hot, they recover their folidity, and become like por¬ 
celain. The phofphat of lime does not melt, but the 
molecules are drawn fo clofe together as to be almoftvi- 
trefied. The calcined bones no longer contain any al¬ 
kali 5 it is by means of this that the fufion takes place, 
and that the calcareous phofphat pafies to the ftate of glafs. 
If bones in pieces, or l'afped, be boiled in water, the 
liquor, when cool, becomes gelatinous and tranlparent. 
Bones may be reduced to a pulp, by boiling in Papin's 
digefer. If entire bones be put into acids, it foftens them, 
reducing them to a kind of membrane ; if with a ftrong 
and aftive acid, as the nitric, not only the earthy part 
will be dilfolved, but the membranous part will be at¬ 
tacked alfo; it grows yellow, and yields, by dillillation, 
the oxalic and Pruffic acids. 
Calcined bones are foluble in all the mineral acids 1 , and 
by. the acetous and tartareous acids. The pholphoric 
acid diflolves bones more readily than the others. If a 
folution of bones in an acid be precipitated by an alkali, 
you have, according to Scheele, a combination of the al¬ 
kali with the acid, and the calcareous phofphat is fet free. 
Sulphuric acid has alfo the property of decompofing bones : 
fulphat of lime is formed, and the phofplioric acid re¬ 
mains uncombined. This, as we have feen, is the procefs 
for obtaining pholphorus. 
Of the PUTREFACTION of ANIMAL SUB¬ 
STANCES. 
Organical matters being different from inorganic, muff 
undergo a different procefs in their changes, the one be¬ 
ing vegetable, the other animal: the former ferment, the 
latter putrefy. Fourcroy divides putrefaftion into fix 
parts : its hiitory, caufes, phenomena, nature, the art of 
Hopping it, and the means of preventing it. 
I. PutrefaClion called by Boerhaare Fermentation. —In 
this operation nature exhibits a curious phenomenon to 
the minute enquirer. Bacon was aware of its import¬ 
ance; and the advice he gave to phyficians, though fol¬ 
lowed, leaves much ftill to be done. Rouelle has been 
employed upon thisfubjeft; but Pringle has treated it 
the belt. Macbride examined the affinity between fixed 
air and animal fubflances; he ©bferved, in putrefaction, 
i. That fixed air was difengaged. z. That, by putting 
putrefying fubflances with fixed air, the putrefaction flop¬ 
ped, was even retrograded. 3. That all animal fubflances 
which afforded fixed air, were anti-feptics. 
II. Caufes of Putrefaction. —There is no putrefaftion in 
animal fubflances without the prefence of water; the heft 
preventive, therefore, is very dry air: hence the burn¬ 
ing fands of Libia preferve bodies by depriving them of 
their water. Below o, or zero, there is no putrefaction ; 
a little above, it proceeds but (lowly ; at 15 0 it is more 
haflened. Animal fubflances have in themlelves a caufe 
which renders them more or lefs liable to putrefaClion. 
The albuminous and fibrous parts are called more ani- 
malized, as being nearer to the ftate of fermentation. All 
thefe fubflances pafs the acid fermentation before they 
become putrid. 
III. Procefs of PutrefaClion. —Every animal fubflance has 
its own peculiar mode and time of fermenting, when ex- 
pofed to a warm moift air. Thefe phenomena may be 
diftinguifhed into general and particular. The general 
appearances are always the fame. There are fix changes: 
3. Of confidence. 2. Of colour. 3. Of fmell. 4. Of 
organization. 5. Of bulk and weight. 6. Of nature; it 
becomes a kind of inorganical earth, in which vegetable 
f ubflances (hoot out and grow. 
IV. Nature of PutrefaClion. —Fourcroy made fome in- 
terefling experiments in the pits of the ci-devant burial- 
place of the Innocents at Paris. He obferved, that when 
lime was thrown upon bodies newly put in, the workmen 
could not remain any time in the pits; they were forced 
[ S T R Y. 
to retreat to avoid an afphixy or apolexy ; their eyes were 
r£d, and they felt great pain. Fourcroy went down : he 
found that the effect arofe from the difengagement of 
ammoniac; he difcovered, alfo, that what the workmen 
called fat snatter, was only ammoniacal foap. 
When putrefaftion is complete, many elaftic fluids of 
a dangerous nature are difengaged. Compound fubllances, 
by putrefaction, pafs to a more fimple (late : thus, if car¬ 
bon unite with oxygen, carbonic acid is formed; if it 
is phofphorus, it will be phofphoric acid; if fulphur, 
fulphuric acid; if phofphorus or fulphur combine with 
hydrogen, fulphurated or phofphorated hydrogen gas will 
be the refult, which will burn, if brought in contaft with 
the air : this combination has given fupport to fome fu- 
perllition among the ignorant. If carbon unites with 
hydrogen, oil is produced ; if azot with hydrogen, it be¬ 
comes ammoniac; laftly, if the azot is difengaged, it 
unites with the oxygen of the air, and forms nitric acid. 
There is alfo a great difference in the progrefs of putre¬ 
faClion. Some fubflances decay rapidly, others flowly, 
as in argillaceous or fat earth. All change, according to 
the fubllances with which they come in contaCl: hence 
it may be difcovered why fome tend to vitrification, others 
turn to manure, and how fome pafs to the mummy or fat 
ftate. It has been propofed to bury dead animals in con¬ 
taCl with humid Alliances, iri order to convert them into 
fat, which may be ufed for burning in lamps. 
V. Of preferring Bodies from PutrefaClion. —In the fat 
matter, there is a part which leems to remain unchanged, 
and Hill furniflies gluten; it is this which tends to the 
prefervation of mummies. 
VI. To fop the Progrefs of PutrefaCiion. —To prevent 
putrefaClion, we mull remove the caufes which produce 
it. Whatever abforbs humidity, is antifeptic ; as, alka¬ 
lis, lime, acids, andfugar; all the neutral falts, efpecially 
thofe with an excefs of acid, all aromatics, all the labiated 
plants, fimarouba, pomegranate-peel, dry balfams, gum- 
refins, &c. may be ufed with fuccefs. To keep infeClion 
from cities, burying-places, common fevyers, &c. thefe 
places fliould be fo difpofed, that fecal matter may always 
be carried off by a llream of running water. 
The art of dellroying the effeCts of putrefaClion, is to 
difengage the muriatic acid from the muriat of foda by 
fulphuric acid ; the fame elfeCl may be produced by oxy¬ 
genated muriatic acid, which deflroys colours and lmells 5 
and, as Fourcroy obferves, might be ufed as an odorimeter 
in anatomical refearches : the bodies might alfo be rub¬ 
bed with oxygenated muriatic acid. It was proved by 
Guyton, as far back as 1773, that the fumes of the mi¬ 
neral acids poffefled the property of flopping contagion. 
This chemift, by means of the fumes of muriatic acid, 
extricated from the muriat of foda (fea fait) by the ful-- 
phuric acid, purified the air of the cathedral of Dijon, 
which had been fo much infeCled by exhumations, that 
they were obliged to abandon the building. The procefs 
was afterwards publifhed under the form of “ Inllruc- 
tions for purifying the air in the military liofpitals of the 
French republic;” a copy of which appeared in the Jour¬ 
nal de Phyfique. The procefs confilted in removing the 
patients, heating fome common fait, previoufly moiftened 
with water, upon a flove, and then pouring fulphuric 
acid upon the hot fait. In an inflant the fulphuric acid 
begins to aft upon the fait, combines with its foda, and 
dilengages its acid, which rifes in the Hate of vapour. 
The operator then leaves the room, and (huts the door; 
and, after twelve hours, returns, and opens the windows, 
to admit frefh air. 
Dr. Carmichael Smith, F. R. S. deferves great praife for 
his meritorious perfeverance in this difcovery, till he got 
the ufe of acid fumes introduced into the Englifh hofpi- 
tal (hips, in 1796 ; and his fubftituting nitre for common 
fait was a happy improvement; for, though acid fumes 
were known to prevent infeftion, there was no proof of 
their having contributed, at the fame time, to the reco¬ 
very of the lick, till thefe experiments w;ere made accord- 
