PUTREFACTION. 



riiighl allege many other circiimftancfs of a fimilar nature. 

 On the other hand, a fcorching heat alfo prevents piitre- 

 faiitioii ; probably by expelling the moidure whicli is eflen- 

 tial to the procefs, becaufe by an inferior degree of heat 

 putrefnftion is promoted. The influence of temperature 

 on animal putrefaftion is thus dated by Becher : " Acr 

 calidus et humidus maxime et pntrefaftionem facit — corpora 

 frigida et fitcadjfficulter, imo aliqua prorfiis non putrefcunt: 

 qux ab imperitis proinde pro fanftis habita fuere ; ita acr 

 frigidus el ficcus, imprimis calldus et ficcus, a putrefac- 

 tione quoque prefervat : quod in Hifpania videmus, et locis 

 aliis culidis, licco, calido acre prjeditis, ubi corpora non 

 putrefcunt et refolvantur ; nam cadavera in oriente in 

 arena, imo apud nos arte in furnis, ficcari, et fic ad fmem 

 niundi ufque a putredine pra;fcrvari, certum eft : inteiifum 

 quoque frigus "a putredine praefervare : unde corpora Stock- 

 holmix tota Iiyeme in patibulo fufpenfa fine putredine ani- 

 madvertimus." From the fafts already ftated, we may de- 

 dnce the molt efFeftiial means of preventing, and increafing 

 putrefaction, and alfo of modifying it at pleafure. A body 

 may be preferved from putrefaftion by depriving it of the 

 contaft of atmofpherical air : for this purpofe nothing 

 more is required than to place the body in a vacuum, or to 

 envelope it in a covering, which may defend it from the 

 immediate aftion of air ; or alfo to envelope it in an at- 

 mofphere of fome gafeous fubftance, which does not cou- 

 tain vital air. Putrefaftion may alfo be favoured by keep- 

 ing bodies at a fuitable temperature. A degree of heat 

 from between fixty-five and ninety degrees diminilhes the 

 adhcfion of the parts, and favours the aftion of the air ; 

 but if the heat be greater, fays Chaptal, it volatihzes the 

 aqueous principle, dries the folids, and retards the putrefac- 

 tion. Hence it is inferred, that for the decompofition of 

 ah animal fubftance, it is neceflary that it ftiould hare the 

 contaft of atmofphcric air, and that the purer the air is, 

 the more fpeedy will be the putrefa£tion : that it be expofed 

 to a moderate degree of heat : and that its texture be im- 

 pregnated with humidity. 



The moit fudden and remarkable changes produced upon 

 a body by putrefaction, are upon its colour, fmell, and tafte. 

 Fle(h beginning to putrefy, is well known to exhale very 

 foon after a penetrating foetid fmell, its colour becomes pale, 

 then inclining to blue, and afterwards livid and black, and 

 its tafte nauleous. Tranfparent liquor, as urine and broth, 

 during putrefaction, becomes alfo turbid : as the putrefac- 

 tion advances, the fmell becomes more and more foetid, and 

 it alfo acquires great pungency, which is caufed by a large 

 quantity of volatile alkali, difengaged from thofe fubftances 

 that are completely putrefied. Solid bodies, whilft they 

 are putrefying, fwell, become foft, lofe the cohefion of their 

 parts, and are laftly reduced to a very difagrecahle putrid 

 pulpy mafs : the fluids become turbid, and the effluvia are 

 loathiome and fickening, and after a time a putrid gas is 

 difengaged in a flow but fenfible effervefcence. A foul and 

 brown ferum then fweats out from the pulpy mafs, and 

 about this time the effluvium is very fenfibly ammoniacal, 

 which is indicated by its eftefts on the eyes and throat, and 

 by forming a white vapour with muriatic acid gas. For 

 fome time a large part of the putrid fubftance is evapo- 

 rated, and carried off in the putrid gas and difperfed in the 

 atmoiphere, after which the extreme fcrtor fubfides ; and 

 finally the procefs of putrefadtion ceafes, and leaves a kind 

 of fat fcetid earthy matter. All the gafes certainly known 

 to be produced by putrefaftion, are carbonic acid, carbu- 

 rettcd hydrogen, fulphuretted and phofphuretted hydrogen, 

 and ammonia ; but either thefe, or fome of thefe, muft be 

 sonfiderably changed by the folution of the animal matter ; 



or fome compound not yet examined, mud be produced in 

 that ftate of putrefaftion, when the gas evolved occafions 

 fuch dreadful effedts upon thofe that have the misfortune to 

 fall in the way of it, even when diluted coniiderably with 

 common air. This is faid to be the cafe when the abdomen 

 of a large animal is firft burft, after iome days or perhaps 

 weeks of putrefaftion ; the gas from which caufes inftant 

 fainting, and fometimes death, and even when the perfon 

 expofed to it receives the firft (hock, it leaves exceliive de- 

 bility and other alarming fymptoms for a conliderabls time. 

 Tlie moft deleterious gas that is known is, perhaps, car- 

 buretted hydrogen, but the eifcdts of this, as obtained by 

 chemical means, are far iliort of thofe above-mentioned, 

 when equally diluted. The generation oi ammonia has been 

 fatisfaftorily accounted for, fmce the difcovery of the con- 

 ftituent parts of the volatile alkali, by the new combination 

 formed between the azote of the animal matter, and the 

 hydrogen, of which latter there are many fources, and par- 

 ticularly that of the decompofition of water. As ammonia 

 is always produced during putrefaftion, it feems rational to 

 fuppofe, that one important purpofe of the moifture necef- 

 fary to the procefs, is to afford, by its decompofition, the 

 hydrogen of the volatile alkali. The nitrous acid is alfo an 

 undoubted produft of putrefaftion ; but farther experiments 

 and fafts are neceflary for explaining the reafon, why in 

 fomecafes the azote tends to unite with oxygen to form this 

 acid, and in others with hydrogen to form ammonia. For 

 an account of the peculiar chanires which animal flefti under- 

 goes, by which it is converted into a fpermaceti-like fub- 

 ftance, initead of pafiing through the ufual procefs of putrid 

 decompofition, we refer to the article Adipocike. 



Sir Jolin Pringle has obferved, that, as all the humours 

 of all animal bodies become thinner by putrefaftion, fo the. 

 folid or fibrous parts are thereby relaxed, and rendered more- 

 teiider : and hence the extraordinary bulk of the heart, liver, 

 and fpleen, incident to pcrfons labouring under putrid 

 difeafes, may be accounted for. It is remarkable, that in 

 diffeftions of perfons who die of the plague, the heart is 

 almoft always found of an uncommon magnitude ; and as 

 to the fcurvy, the liver and fpleen are fometimes enlarged 

 to fuch a degree, that the tumour may be feen outwardly. 



From matters completely putrefied may be obtained by 

 diftillation volatile alkah, fome hquid and fome folid ; a 

 pungent foetid oil, which at firft is thin, and afterwards be- 

 comes more thick ; and a rcfiduum of coal, not eafily redu- 

 cible to aflies. Some writers on this fubjeft have appre- 

 hended, that putrid fubftances are not to be regarded as 

 alkaline. Sir John Pringle, finding from the experiments 

 which he made in the year 1750, that fyrup of violets was 

 not changed into a green colour by the ferum of putrid 

 blood ; that this ferum did not make any effervefcence, 

 when fpirit of vitriol was poured upon it ; that water, in 

 which corrupted flefli had been for fome time infuied, neither 

 effervefced nor changed the colour of the fyrup ; and that 

 alkahne falts, both fixed and volatile, powerfully oppofe 

 putrefaftion ; was led to adopt this opinion. But wheji he 

 became acquainted with the experiments made by M. J. Bapt, 

 Gaber of Turin (Adta Taurinenf. vol. i. p. 78, &c.) he 

 embraced with the liberality of a true philolopher, the firft 

 opportunity of acknowledging his miftake. M. Gaber, 

 having poured a drop or two of aqua fortis upon bile, taken 

 out of the gall-bladder of a perfon who had died ot an inve- 

 terate jaundice without a fever, and whofe body had lain 

 about twenty-four hours in a cold place in winter, found, 

 that the mixture immediately effervefced, became fenfibly 

 warm, and that feveral air-bubbles rofe to the iurlace. H« 

 alfo expofed the remainder cf this bile in three open glaffes 



O 3 te 



