PUTREFACTION. 



to thf- thirty-fifth, twenty-fifth, and tenth degrees of heat, 

 indicalsd by Rcaiiimir's thermometer, and at the end of 

 twenty-four hours mixed them with acids; and he found, 

 that the bile which had been placed in a degree of heat au- 

 fweririjf to thirty-five, was molt dilated, and gave very flight 

 indications of effervefcence ; that which had flood in twenty- 

 five was alfo dilated, and the acid produced a more fenfible 

 effervefcence, but ItiU very flight ; and the bile wliich had 

 been expof-d only to the temperament of the air, varying 

 from feven to ten, preferved its tenacity, and fermented as 

 much as that in his firlt experiment. Having mixed fome 

 blood, taken out of a vein of tiie dead body at the lame 

 time, and which appeared to be of the yellowilh-rcd, with 

 fpirit of nitre, the mixture effervefced, but in a much lefs 

 degree than the bile : this mixture, being left to digeft for 

 fome hours, a yellow ferum feparated from the blood, and 

 covered its whole furface ; and the blood, being lubjedted 

 to the fame heat as the bile, and for the fame time, ap- 

 peared more difpofed to effervefce than the bile, though this 

 difpofition afterwards gradually diminidied. From thefe 

 experiments the ingenious writer infers, that in difeafed bo- 

 dies the humours may become fo alkalefcent as to effervefce 

 with acids : that a very flight degree of putrefaftion and 

 fator, which is not fufficient to produce alkalefcence out 

 of the body, will produce it in the body ; that alkali formed 

 in the body, and contained in the bile, is extremely volatile, 

 fince the heat of twenty-five degrees made a great part of it 

 evaporate ; and that the fame alkali contained in the blood, 

 being a little more entangled vi'ith other elements, is confe- 

 quently lefs volatile, fince the fame degree of heat continued 

 for the fame time, difTipated but a very inconfiderable part 

 of it : and, therefore, that the different phenomena taken 

 notice of by thofe who have profecuted experiments of this 

 kind, fome of whom affirm that they have feen undoubted 

 proofs of the prefence of an alkali, and others that they 

 have fcarcely difcovered any iuch indications at all, are the 

 effefts of different degrees of heat, the flalenefs of the fub- 

 flance expofed to the heat, or the different volatility of the 

 alkali arifii-ig from its coheCon with other principles. Having 

 made fimilar experiments upon healthy bile, blood, and 

 ferum, and fubraitted them to the action of mineral acids, 

 he found the bile mofl difpofed to effervefce ; that human 

 bile was more difpofed to effervefce than the bile of an ox ; 

 that corrupt blood ferments with acids ilill flower; and that 

 ■ferum ferments ffower than blood. He alfo obferved, that 

 putrefcent humours not only effervefce with mineral acids, 

 but with very weak diftilled vinegar : and that thofe hu- 

 mours that have been expofed to artificial heat, become 

 foetid and effervefce fooneft, and foonefl arrive at the laft 

 (tage of fermentation ; in which cafe the fermentation ceafes, 

 though the heat is continued ; and the fmell, which till then 

 is intolerably foetid, becomes herbaceous^ and is not dif- 

 agreeable. The factor, he fays, manifefls itfelf fooner and 

 lails longer than the alkalefcence. 



M. Gaber farther obferves, in relation to the experiments 

 of fir John Pringle, that at the degree of heat to which he 

 expofed putrefcent fubflances, and which was equal to the 

 hundredth degree of Fahrenheit, correfponding nearly to the 

 thirtieth degree of Reaumur, animal humours very foon be- 

 come putrid ; but that they as foon lofe the alkalefcence 

 which they derive from putrefattion, if this degree of heat 

 is continued : fo that as the corrupting humours manifefl 

 their alkalefcent quality only for a very fhort time, it might 

 eafily happen that no fign of alkalefcence appeared in his ex- 

 periment, if it was not made in the critical moment, /. e. if 

 he examined the putrefcent humours a little before the alkali 

 was formed, or a little after it had evaporated. And he, 



therefore, apprehends, that if fir John Pringle's experiments 

 were made with a degree of heat jull equal to his own, the 

 refult, ctsteris paribus, mull have been the fame. 



From other experiments this writer infers, that blood re- 

 ceived from the arm, agitated and left to putrefy, does not 

 putrefy fo foon, nor fo foon manifefl figns of alkalefcence, 

 as the red part feparated from tlie ferum, becaufe the ferum 

 putrefies more flowly than any other animal humour ; and that 

 the alkali, which evaporates with a degree of heat from twenty- 

 five to twenty-eight of Reaumur, being collected in a receiver, 

 will effervefce, and that the refiduum is a mafs extremely 

 foetid, wholly delHtute of alkali, and, confequently, that no 

 effervefccnce is to be expeftcd by pouring acids upon it. 

 Having kept fome blood in a glafs vefiel clofe flopped, he 

 found that it retained its alkalefcence a long time, though ex- 

 pofed to a degree of heat equal to twenty-five ; but upon un- 

 flopping the vefiel, it flew ofl with great violence, in an ex- 

 tremely foetid vapour. Thefe explofions he attributes to the 

 expanlion of the air, in cor.fequence of the putrefaction ; and 

 hence he deduces the reafon, wiiy the humours that are con- 

 tained in the veffels of a human body become alkalefcent 

 while they are yet fcarcely foetid, although when drawn 

 from the body, and kept in open veffels, they become foetid, 

 before they give figns of alkalefcence. As foon as they begin 

 to form alkali in the veffels, the alkali is retained ; but as it 

 exhales from veffels expofed to the air, a greater quantity 

 mull be formed than exhales before it can become fenfible. 

 Having collected the difliUcd liquor of blood in fuch a itate 

 of putrefcence as to effervefce with acids, and expofed it to 

 the aftion of various acids, a violent effervefccnce enfued ; 

 and when poured upon fyrup of violets, it produced as fine 

 a green as fpirits of hartfhorn ; and this tinfture, having been 

 changed into a red by the effufion of a few drops of aqua 

 fortis, became again blue, upon pouring into it fome more 

 of the diHilled hquor ; whence he concludes, that putrefcent 

 humours form a true alkali, which exhales with a very flight 

 heat. From other experiments he infers, that the alkali of 

 putrefcent fubflances is not the produftive caufe of their 

 foetor, becaufe the latter remains when the former is departed. 

 But as both appear in the fame degree of heat, when long 

 continued, it appears, he fays, that this foetor is produced 

 by the effluvia of parts extremely volatile, but different from 

 volatile alkali, which, though fooner produced, are more 

 flowly diffipated. Alkalefcence, however, may be fome- 

 times connefted with a flight fostor; and, on the contrary, ex- 

 treme foetor may fubfifl without alkalefcence. And this 

 fail confirms the obfervation of fir John Pringle, who found 

 a difference between the foetid and alkahne particles ; fince 

 the exhalations of frefh urine are not pernicious, though they 

 contain more alkah than any fubilance in a flate of pu- 

 trefaction, the odour of which is pernicious in the higheft 

 degree; and, therefore, putrid effluvia are of a different na- 

 ture from alkaline falts. M. Gaber farther adds, by way of 

 inference from this fadl, that a volatile alkali is not a ne- 

 ceflary produdl of putrefattion, and that the degree of 

 alkalefcence is not equal to that of putrefaftion. Dr. 

 Crell, profeffor of chemiflry at Brunfwick, has objected to 

 this doftrine, as not conformable to the phenomena (Phil. 

 Tranf. vol. Ixi. part i. art. 39.) ; for he fuppofes, that as 

 all fmell depends on a faline matter joined with phlogiflon, 

 and the faline matter producing the putrid flench was very 

 probably not an acid, it mutt be a volatile alkali, v.hich, 

 involved in phlogiflic matter, might fly off before the alkali 

 was developed. From fome experiments made with a view 

 of afcertaining this fail, he infers that the volatile alkali is 

 prcfent as long, at leall, as the putrid fmell continues, and 

 that this volatile alkali is the bafis of it ; becaufe, as this was 

 9 difliUed 



