PUTREFACTION. 



If now tliis fcctid matter, thus obtained, be dirtftly, 

 whilft it remains in its Txtid ftatc, committed to a glals re- 

 tort, and dillilled witli pr()i)er degrees of fire, there will 

 come over, i. A water impregnated with an urinous fpirit, 

 porfeftly hke that obtainable from animal fubjeds, and fe- 

 parable by a frefh dillillation flovvly made in a tall glafj,, 

 into elementary wat^j-, and a large quantity of pure, white, 

 volatile, dry, alkaline fait, not to be dillinguilhed from 

 animal i'alts. 2. A vi)latile, alkaline, oily fait, that ftioots 

 into globes. 3. An exceedingly volatile and thick fcetid 

 oil, both which are entirely like thofe of animals. And, 

 lallly, the remainder, being calcined in an open tire, af- 

 fords not the leall particle ot iixed fait ; jull as if the fubjcft 

 had really been of the animal, and not of the vegetable 

 kingdom. 



This procefs is truly univerfal, and holds equally in all 

 kinds of vegetables, though ever fo different in then' nature 

 and virtue. 



Experiments have been made in the coldeft and mofl fuc- 

 culent, or watery, plants ; fuch as purflane, forrel, &c. as 

 well as with the hotteil or mofl acrimonious, luch as the 

 fpurges, &c. and it was always found to fncceed ; but that 

 the fooner, as the vegetable employed contained the greater 

 quantity of oil ; though with the fame phenomena. 



It will likewife fucceed witii dry vegetable?, provided 

 they be moiftened with water before they are thrown into 

 heaps ; and thus we fometimes fee, that ftacks of hay will 

 fpontaneoufly take fire, and burn away ; efpecially if the 

 hay was not well dried in the making. 



The conditions neceffary for the putrefadlion of vege- 

 tables are fimilar to thofe required in the putrefaftion of 

 animal fubflances. It is neceiiary that the organization be 

 impregnated with water ; the contaft of air is neceflary, as 

 is ;ilfo a certain degree of heat ; and for the due effett of 

 this kind of decompofition, the vegetables fhould be heaped 

 together, and their juices be abundant. In thefe circum- 

 ilances, the phenomena of decompofition are as follow : 

 the colour of the vegetable is changed ; the green leaves be- 

 ■■ome yellow, the texture becomes lax, and the parts lefs 

 i:oherent ; the colour of the vegetable itfelf changes to black 

 or brown ; the mafs rifes, and perceptibly fwells up ; the 

 heat becomes more intenfe, and is perceived on approaching 

 the heap ; and the fumes which arife have already a fmell, 

 which fometimes is not difagreeable ; at the fame time 

 bubbles arife, and break at the furface of the liquid, when 

 the vegetables are reduced to a magma. This gas is a mix- 

 ture of nitrogene, hydrogene, and carbonic acid. At this 

 epocha, hkewife, an ammoniacal gas is emitted, which is 

 formed in thefe circumllances : and, in proportion as thefe 

 appearances diniinilh, the ftrong and offenfive odour is fuc- 

 ceeded by another which is fainter and milder, and the mafs 

 becomes dry. The internal part Hill exhibits the vegetable 

 ftrudlure, when the ilcm is folid, and the fibrous matter has 

 been the predominating principle ; and it then conftitutes 

 manure or foil. Hence it arifes that the herbaceous plants 

 of a loofe texture, and abounding in juices, are not capable 

 of forming manure by their decompofition, but are reduced 

 into a brown mafs of httle confiilence, in which neither fibre 

 nor texture are obferved ; and this is what, for the mofl 

 part, forms vegetable mould. 



Vegetable mould ufually conftitutes the firft covering or 

 ftratum of our globe ; and in fuch cafes wherein it is dif- 

 covered at a depth in the earth, there is no doubt but it has 

 been buried by fomo revolution. 



When a vegetable is converted into earth by this tu- 

 multuous fermentation, it ftill retains the remains of the 

 vegetable, mixed and confounded with the other folid earths 



and metallic produfts ; and by diflillation it aflords oil, ni- 

 trogene gas, and often hydrogene. It may, therefore, be 

 confidired as an intermediate fubflance between crude and 

 organic bodies, whicli participates of the inertia of the one, 

 and the activity of the other ; and which in thi:; flate is dill 

 fubjecl. to an infcnfible fermentation, that changes its nature 

 flill more, and deprives it of all its organi.c contents. Thefe 

 r mains of vegetables, llill contained in vegetable earth, 

 fcrve as food for other plants that may grow in it. The 

 infenfible progrefs of fermentation, and the fuftion of vege- 

 tables, impovcritli the vegetable earth, deprive it of all its 

 or vanic matter, and there remain only the earths and me- 

 tallic refidue which form the (lifF poor foils, and ochres 

 when the ferruginous principle is very abundant. 



As this muddy earth is a mixture of all the primitive 

 earths, and fome of the metals which are the produdl of 

 vegetation, as well as the oils, the falts, and other produfts 

 we meet with in it ; we may confider it as the rclldue of 

 vegetable decompofition, as the great agent and means by 

 which nature repairs the continual lofTes the mineral king- 

 dom undergoes. In this mixture of all the principles the 

 materials of all compounds exifl ; and thefe materials are fo 

 much the more difpofed to enter into combinations, as tkey 

 are in a more divided and difengaged ftate. It is in thefe 

 earths that we find diamonds, quartz-cryflals, fpars, gyp- 

 fum, &c. It is in this matrix that the bog ores, or 

 ochreous ores of iron, are formed ; and it appears that na- 

 ture has referved the impoverlflied refidue of vegetables for 

 the reproduftion or reparation of the earthy and metallic 

 fubflances of the globe, while the organic remains are made 

 to ferve as nourifhment for the growth of other fucceedinj 

 vegetables. 



Some have taken occafion to apply the procefs of putre- 

 fadlion to that of digeflion, or the change which the aliment 

 fuffers in the human body. (See Digestion.) For the 

 change our vegetable foods undergo in the body, being fuch 

 as brings them to be of the fame nature, and to afford the 

 fame principles, with the change induced by putrefaftion, 

 is a prefumption, that digeflion is nothing elfe. Befides, as 

 we know that neither animal nor vegetable fubflances can 

 become aliment, without undergoing fome degree of putre- 

 faftion, many diilempers mufl proceed from a deficiency of 

 this aftion : the crifis of fevers feems to depend upon it ; 

 and even animal heat, according to Dr. Stevenfon, does the 

 fame. 



Now, that the concoftion of the humours is nothing elfe 

 but putrefaftion, feems probable from hence, that when- 

 ever they are in that flate, they are aUvays more fluid, and 

 fitter to pafs through the fmaller velfels, where they flag- 

 nated before. Again, the offenfivenefs ef the fweats, or 

 otlier excretions confequent on a crifis, is likewife a fure 

 fign of a high degree of corruption. The time of refolu- 

 tion or putrefaftion depends on the degree of heat, the 

 habit of the patient, and on the part obftrufted. Refolu- 

 tion is the putrefaftion of the impafted humour only, but 

 luppur.ation implies a corruption of the veffels alfo. This 

 manner of fpeaking, indeed, has been difufed, from the pre- 

 judice that nothing was putrid but what was ofFenfively fo ; 

 whereas, in faft, every fibre becoming more tender, and 

 humour thinner, may be confidered as putrid in fome degree, 

 whether the change tends to the better health, or to the de- 

 flruftion of the perfon, or whether it becomes grateful or 

 offenfive to the fenfes. 



Mr. Boyle has ufed the wordi fermentation znA putrefadion 

 of the blood promifcuoufly, in his Treatife on the Human 

 Blood. Stahl and other celebrated cheraifts likewife ufe the 

 termputrid/frmM/; which fee. 



It 



