PUTREFACTION. 



particles of bodies. Mr. Macbride, as we have elfewhere 

 mewn, has taktii occalion, by :i variety of experiments, to 

 JUullrate and eftablifli this opinion ; and in fupport of it he 

 alleges, that the prefervation of finnnels and foundnefs in 

 bodies depends oh reftraining the efcape of that principle, 

 fince known by the name of fixed air, and which he fup- 

 pofes to be the immediate caufe of cohefion : for the mo- 

 ment it flies off and refumes its clailicity, the other conlli- 

 tuent particles, vk.. tiie earthy, the faline, the oily or in- 

 flammable, and the aqueous, being thereby put in motion, 

 immediately begin to exert their feveral peculiar attra£live 

 and repulfive powers, and run into new combinations, which 

 firil change, and at length altogether deflroy the texture 

 of the fnbftauce they formerly compofed ; provided that 

 this fubilance contained in itfelf a fufficient quantity of 

 water to allow of the intefline motion, by giving the proper 

 degree of fluidity ; for without fluidity there can be no 

 inteftine motion ; and without inte tlinc motion there can be 

 no change of combination : beca\ife we fee that fuch animal 

 and vegetable bodies as are fuddenly deprived of their water, 

 or naturally contain very little, are almoft as durable and 

 unchangeable in their texture as minerals. Hence Acofla 

 obferves, that in Peru, and others have obferved the fame 

 in Egypt, wiiere it very rarely rains, every thing will con- 

 tinue a long time uncorrnpted ; uiilefs we fliould rather 

 afcribe this effeft to the abundance of nitrous fait in the air 

 of thofe places, which is known to refill putrefaftion. In- 

 deed all putrefattions, both of animal and vegetable bodies, 

 are affirmed by the learned Boerhaave to be performed by 

 means of water alone. Take, fays he, a pound of frefti fiefh, 

 and keep it in a heat like that of our body, and, in a few days 

 the putrefaftion will be completed; but if you firft drain 

 out, or exhale, all the watery part from the fame in fome 

 chemical veflel, though the fait and oil remain, the flefii will 

 harden like a ilone, and may be kept for ages without 

 putrefaftion. Though whei\ thus hardened, water poured 

 on it, or even the common dew, will foon fet it a putre- 

 fying. Thus Villaris and Cazalet of Bourdeaux, as Chap- 

 tal informs us, dried meat by means of floves, whicli was 

 preferved for feveral years without contrafting any bad 

 flavour. 



By fuch means, bread, flefh, or the like foods, may be 

 preferved for many ages ; provided regard be had to the 

 place. Hence it is that in dry cour.tries, as Egypt, dead 

 carcafes never putrefy, but dry and harden uncorrupted : 

 as we fee alfo in the mummies found buried under the 

 fand. 



The fands and light porous earths preferve human bodies 

 by exhaufting their juices and drying the folid parts. Hence 

 it is, that entire caravans have been difcovered in Arabia, 

 confiding of men and camels, preferved in the fands under 

 which the impetuous winds have buried them. In the 

 library of Trinity college, Cambridge, a human body may 

 be feen in a perfect, ftate, which was found under the fand 

 in the ifland of Teneriffe. Hence fubilances putrefy much 

 more flowly when expofed to a drying wind, than in a 

 fheltered place. 



Neverthelefs, too much humidity impedes putrefaftion. 

 To this purpofe Bccher obferves : " Nimia quoque humi- 

 ditas a putrefaftione impcdit, prout nimius calor ; nam 

 corpora in aqua potius gradatim confumi quam putrefcere, 

 fi nova femper aflfluens fit, experientia docet : unde longo 

 tempore integra interdum fubmerfa prorfus a putrefaftione 

 immunia vidimus ; adeo ut nobis aliquando fpeculatio occur- 

 reret, tra£tando tah modo cadavera anatomia: fubjicienda, 

 quo diutius a foetore et putrefaftione immunia forent." Ac- 

 cordingly it is necefl'ary, that in order to a body's putre- 

 4 



fying by moifture, that tlie water fliould impregnate but 

 not mundate it. It is alfo ncceflary, that it ihould re- 

 main in the texture of the animal body, without being re- 

 newed ; for thus the lymph is diflolved, and the molt 

 putrefcible fubfl^ance is prefented to the air with the greatefl- 

 extent of furface ; and the water itfelf is decompofed, and 

 by tliis means affords the putrefaftive principle. 



Even human blood, which, naturally, is fo prone to 

 putrefaftion, if you deprive it of its watery part, may be 

 kept for fifty years. Goat's blood, we actually find kept 

 fo long in the fltops, without corrupting ; though, if you 

 diflbve it in water, and expofe it to a gentle warmth, it 

 will putrefy immediately. Blood is faid tu be the mod pu- 

 trefcent animal fubft;ance that is known ; and this property 

 is afcribed partly to its fluidity and partly to the large 

 quantity of fibrin and uncondcnfed albumen, which it con- 

 tains, and efpecially to the former. See Blood. 



We fliaH here add, that animal fubltances feem to be (cxterii- 

 paribus) more putrefcent in proportion to the number of 

 conflituent parts which they contain. The fubilances either 

 abfolutely or nearly imputrefcible are bone and condenfed 

 albumen, the latter being fuch as exiils in cuticle, nail, 

 hair, &c. which long remain unaltered in the midll of putre- 

 fying fubilances. Animal oil alfo putrefies with great dif- 

 ficulty, and hence the people that live in the moil northern 

 parts of America, the Efquimaux and others, preferve fifh 

 and meat to a certain degree from putrefaction by immcrfion 

 in fifli-oil. 



In p';trefaclion there is a great inteftine motion, which, 

 when carried to an extreme, and when the putrefying fub- 

 ftance is. much comprefTed, is accompanied with heat and 

 fmoke, and fometimes flame. However, M. Beaume affirms, 

 that putrefaftion is not attended with any fenfible heat : 

 when, indeed, it proceeds flowly, and the quantity of putre- 

 fying matter is but fmall, the heat, if any, is very little. 

 That putrefcent fubilances emit hght, is an unqueflionable 

 faft ; and on this principle philofophers account for the 

 luminoufnefs of the fca, the ignis fatuus, &c. To this 

 purpofe M. Ant. Martin (Swed. Abhad. vol. xxiii. p. 225, 

 cited by Dr. Prieftley, in his Hiftory of Light, Sec. 

 p. 576.) obferves, that human bodies have fometimes 

 emitted light about the time they begin to putrefy ; and 

 that the walls and roof of a place in which dead bodies 

 had often been expofed, had a kind of dew or clamminefs 

 upon them, which was fometimes luminous. And he ima- 

 gmes, that the fights which are faid to be feen in burying 

 grounds may be owing to this caufe. It has been ob- 

 ferved, that heat extinguiflies the light of putrefcent fub- 

 ilances ; Mr. Canton, attending to this circumltance in 

 fome experiments for afcertaining the caufe of the luminouf- 

 nefs of the fea, remarks, that though the greateft fummer- 

 heat is well known to promote putrefaftion, yet twenty 

 degrees more than that of the human blood feems to hinder 

 it ; for putting a fmall piece of luminous fifh into a thin 

 glafs ball, he found that water of the heat of one hundred 

 and eighteen degrees would extinguifli its light in lefs than 

 half a minute ; but that on taking it out of the water, it 

 would begin to recover its light in about ten feconds : but 

 it was never afterwards fo bright as before. See Light. 



It has been obferved, that a temperature from about 

 forty degrees to the higheft natural heat is favourable to 

 the putrefaftion of animal matter, whereas a freezing tem- 

 perature is known to flop putrefaftion, as it is the cuftom 

 in cold countries to bring viftuals frozen to market, and in 

 this ftate they are kept for any length of time without any 

 other preparation ; and befides, bodies of men or of other 

 animals remain unaltered under ice for many weeks. We 



might 



