ANA

ANA

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compounded, is a very peculiar fluid. AnimalOil, under the various names of Fat, Tallow,Suet, Marrow, 8cc. forms a diftincl clafs. Tothis perhaps may be added, though confiderablydiffering in chemical properties, Wax and Sper-maceti. No animal fluid has occupied moreattention than the Urine , even from the earliefttimes of animal chemiftry.

Befides the foregoing fubftances, there aremany others which have a place in the hiftoryof the analyfis of animal matter, and cannot beeasily, arranged under any general head. Ofthis kind are mulk, caftor, ambergris, &c. whichwill be found under their refpeclive titles.

The chief proximate conftituent parts of theabove-mentioned animal fubftances are: Water,which appears to enter Amply as water into thecompofition of all the folids, to give flexibilityand elafticity to the moving and yielding parts,and to form by far the greater part of thefluids, oil excepted : Fibrin, alfo called Gluten ,found in the blood, and the chief conftituent ofmufcular fleflt: Albumen, much refemblingfibrin in chemical properties : Gelatin or Jelly:Oil: a fpecies of Refn: one or two peculiarAcids -, fome alkaline and earthy falts, chieflySoda and Lime, with the phofphoric and muriaticacids : and alfo a fmall portion of Iron .

The analyfis of all kinds of animal matterprefents a certain fimilarity of refult which veryfatisfadlorily coincides with the fmall numberof elements into which the above proximateconftituents are refolvable. It {hews that Azot ,Hydrogen, Oxygen, and Carbon , perform theleading parts in the innumerable changes bywhich every animal fubftance is elaborated inthe living organs; but the diforganization ofthefe by chemical means gives rife to certaincompounds not to be found in the originalbody.

The analyfis by fire was principally refortedto by the older chemifts, and though lefs difcri-minative than the ufe of reagents, it is highlyinftructive. All the hard, the.foft, and the fluidparts of animals (the latter being previoufly eva-porated. nearly to drynefs) if put into a retortwithout addition, and heated firft flowly andafterwards to ignition, exhibit nearly the follow-ing appearances: 11 a watery fluid firft clear,afterwards brown and turbid, diftills over : thiscontains fome ammoniacal falts, and foon aftercarbonat of ammonia comes over, part of whichdiflolves in the liquor, and part cryfUillizes onthe neck and fides of the receiver. To this fuc-ceeds an oil, at firft nearly limpid, but foon

a Fourcroy Syit. de Conn. Chem. k Mem. d

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coloured, thick and foetid. This oil is accom-panied with more carbonat of ammonia partlycryftalline, in part diflolved in the oily vapour.At the fame time a quantity, often very large,of gas pafies over, which is found to be chieflycarbonic acid, but foetid on account of its mix-ture with the empyreumatic oil, and mixed withcarburetted hydrogen, and fometimes fulphu-retted or phofphuretted hydrogen. When no-thing more is given over, and the retort is redhot, if the procefs is flopped, a fhining blackcoal is found, very difficult to burn to afhes,and mixed with the phofphat of lime, and otherfixed matter which the fubftance contained.The chief products therefore of animal matterdiftilled without addition, are water, carbonatof ammonia, animal oil, carbonic acid gas, and arefidue of coal with fixed earthy falts. But ofthefe products fcarcely one is found in this pre-cife combination in the animal fubftance beforediftillation; they are therefore formed out oftheir elements by the action of fire, and hencethe confufion and uncertainty attending the ana-lyfis of thefe bodies before the nature of water,of carbonic acid, of ammonia, and of hydrogen,was underftood. Of thefe products, the volatilealkali is the moft important, for it is generatedin abundance by many changes to which animalbodies are expofed, and is not to be detectedexcept in minute quantities, before thefe changeshave taken place. In the article ammonia, wehave fully {hewn the compofition of this alkalito be azot and hydrogen, and hence it becomesrequifite in accounting for the generation ofammonia, to prove the exiftence of its twoconftituent elements in animal matter. Theprefence of hydrogen is obvious, from thequantity of water exifting in all animal fub-ftances, from the production of oil by diftillation, and the aftual evolution of much hydrogenin a gafeous form, mixed with carbonic acid.The prefence of the azot has been demon-ftrated in an equally fatisfaclory and very in-genious manner, efpecially by the valuablerefearches of M. Berthollet.

This admirable chemift reforted to the nitricacid as an agent for the decompofition of animalmatter. He found that when filk, hair, wool,and other animal fubftances were digefted withnitric acid with application of heat, a peculiaroily fubftance was produced, and along with ita large quantity of Oxalic acid, h the particu-lars of which experiments will be deferibedunder this acid. In a fubfequent teries of ex-periments, c the fame chemift, purfuing tbq

: l’Acad, des Sciences, 1780. c Ibid. 1 785.

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