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alkali contained in the blood, be experiments, the effervescence was ing a little more entangled with attended with the same phænomeother elements, is, confequently, na that are related, (Par. 1.) Pu. less volatile ; fince the same degree 'trescent humours not only efferof heat, continued for the same vesce with mineral acids, but with time, dislipated but a very incon. very weak diftilled vinegar. The fiderable part of it.

several portions of these humours 4. This observation inclines me that have been exposed to artificial to suspect, that, in other experi- heat, become ferid, and effervesce ments upon putrefaction, in which foonest, and soonest arrive at the some operators affirm, that they 'Taft ftage of fermentation. When have seen indubitable proofs of the this happens, the fermentation presence of an alkali; and others. ceases, though the heat is conti. lay, they have scarce discovered nued; and the smell, which till any indications at all; the diffe. then is intolerably fetid, becomes rence is the effect of different de. herbaceous, and is not disagree. grees of heat, the staleness of the ablet. The fetor manifests itself iubitance exposed to the heat, or sooner, and lafts longer, than the the different volatility of the al- alkalescence. kali, arising from its cohesion with 6. To put the effervescence of other principles.

putrescent humours with mineral 5: The same experiments that I acids beyond a doubt, I must now made upon morbid bile, ' I made observe, that the aqua.

- fortis which also upon healthy bile, upon blood, I used in my experiments was very and upon serum. I divided each weak, and such as produced no of these liquors into three parts, 'motion in common water ; and which I separately exposed to the this effervescence is so far from three different degrees of heat men- being the effect of concentering the tioned above; and having submit. acidst, that, in my opinion, the ed them severally to the action of acids may be fo.concentered as to mineral acids, I found the bile render the effervescence less; prin. soft disposed to effervesce; and cipally because the animal humours Baglivi has observed, that it cor. relift effervescence, in proportion rupts sooner than any other hu." as they unite with acids speedily mour. I found that' human bile and intimately; for when I made was ‘more disposed to effervesce use of distilled vinegar, not strong than the bile of an ox ; that cor- enough to coagulate the putrescent rupt

blood ferments with acids still humours, I observed thai the effer. power, and that serum ferments vescence was equally violent, and flower than blood. In all these I have seen distilled vinegar opee'

• It has sometimes happened, that serum, exposed to an heat equal to 35, has not effervesced; which gives cause to suspect that the alkali contained in it difsipates in proportion to the force and continúance of the heat.

† This always happens in the process of vegetation. All putrescent humours depofited in a warm place foon become rancid, and contract a strong smell, which, after a long time, resembles that of amber.

1 Which is the case with bile not in a putrescent state.

rate

rate so powerfully upon a putrid texture, by continual agitation, I serum, as wholly to convert it into left it to putrify. I observed that froth.

its fine florid red colour insensibly 7. When I was reading Dr. faded to a blackish brown ; but Pringle's experiments upon this this change did not take place in subject, I observed that he some- the whole mass at the same time; times exposed putrescent fubftances it began at the surface, and gradu. to an heat equal to the 100th de- ally descended. gree of Farenheit's thermometer*, 9. Blood in this state does not which is nearly the same with the putrify fo foon, nor so soon give 3oth degree of Reaumur's.--Now, figns of alkalescence, as the red it is certain, that at this degree of part separated from the serum, beheat, animal humours very soon cause the serum putirfies more become putrid; but then they lofe fowly than any other animal huas soon the alkalescence which they mour. derive from putrefaction, if this 10. After having discovered, by degree of heat is continued ; fo the foregoing experiments, that that as the corrupting humours the alkali Aies off with a Night demanifest their alkalescent quality gree of heat, I was desirous to try for a very short time only, it might if I could recover and retain it. I easily happen that no sign of alka. therefore put into an alembic of lescence appeared in this experi- glass, fome serum which had sepament, if it was not made in the rated from blood taken a few hours critical moment: I mean, if he ex. before from a feverish patient, and amined the putrescent humours a I placed it in a degree of heat belittle before the alkali was formed, tween 25 and 28 of Reaumur's or a little after it had evaporated. scale: I passed the neck of the And supposing the experiment to alembic through a hole which was have been critically made, ftill, as made for that purpose, in the the ambient heat would have caused wooden covering of the ftove, that the alkali to evaporate almoft en. the head of it might be in the tirely as soon as it was formed, same temperament with the air of Dr. Pringle would have perceived the chamber, which was equal to very flight tokens of effervescence, about the oth degree of the same though with a lefs degree of heat, scale, and that the exhaling vapour they would have been considerable: might condense there into liquor : consequently, if that ingenious and to the spout of the head of the accurate observer had made his ex. alembic, I luted a bottle as a reperiments with a degree of heat juft ceiver, and at the end of every equal to that with which I made two days I had about two drachms mine, the result, cætaris paribus, of this difilled liquor, upon which would have been the same. I poured acids, with different ef.

8. I received some blood as it fects. That part which came over issued from the arm in a vial; and first, had the smell and taste of sehaving dissolved it, or broken its rum; it was clear and transparent,

* The freezing point in Farenheit's is 32, the boiling 213. On Reaumur's the firft is marked o, the latter 8o.

and did not effervesce either with why the humours that are containacids or alkalies. The next por. ed in the vessels of the human body tion was slightly fetid, but nearly become alkalescent while they are of the fame taste and transparency yet scarce fetid, at the same time as the first; the third diffe red lit. that drawn from the body, and kept tle from the second; but the fourth in open vessels, they became fetid was extremely fetid, foul, opake, before they give signs of alkaleand of a pale colour; it did not, scence. As soon as they begin to however, ettervesce, but acids form alkali in the vessels, the alkali flightly tinged it with red; the is retained, but as it exhales from a fifth, which came over after the vessel exposed to the air, a greater tenth day, and was clear, effervef- quantity must be formed than exced with acids, and produced a hale“, before it can become sensible. hishing which became sensible when 12. As ferum fubjected to the the ear was brought close to the experiment in a sound state did not veffel : it also produced bubbles and give up its alkali in less than ten

: the fixth portion was equal. days, it may be fairly inferred that ly limpid, but effervesced more it does not in less time become slightly, and when I perceived that corrupt, it being certain, in the nothing more would come over first place, that humours corrupt with this degree of heat, I broke flowly in a closed vessel; and, in the alembic to examine the refi- the second place, that of all huduum: I found it a viscous cruft, mours, the serum continues longest resembling wax, of a reddish colour, uncorrupt. and extremely ferid, but the affusion I did not doubt, but that ferum, of acids produced not the least fins already corrupt, would, in diftillaof effervescence. This experi- tion, give up its alkali immediare. ment, I thought, proved to de. ly, I therefore made the same exmonftration, that alkali evaporates periments upon corrupe ferum, that with a degree of heat from 25 to I had made upon found : My prin28 ; that being collected in a re- cipal view was to determine, exceiver, it will effervesce, and that actly, the time when the alkali the resduum is a mass extreinely would begin to fly off, and after fetid, wholly deftitute of alkali, having collected the diftilled li. and, consequently, no effervescence quor, to try whether it would is to be expected by pouring acids change the blue vegetable colour

of violets to a green, which the 11. Some blood which I kept in lowness of the preceding experia glass vessel close ftopped, retain- ment had prevented me from ated its alkalescence a long time, tempting. 'I took for this purpose though it was exposed to a degree fome blood in such a state of pu, of heat equal to 25; but upon un- trescence as to effervesce with aftopping the vessel, it flew off with cids, and having put it into a glass great violence, in a vapour ex-'alembic, I exposed it to the fame tremely fetid. The explofion was degree of heat with the same preprobably caused by the expansion of cautions and apparatus as in the the air, in consequence of the putre- preceding experiments. The firit faction; and this experiment thews day I collected two drachms of the VOL. X.

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dif.

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distilled liquor, which I exposed to 15. But as both the alkalescence the action of various acids, and a and fetor disappear in the same violent effervescence ensued: 1 degree of heat, if long continued then poured some of the same liquor (Par. 5.) it appears that this fetor upon syrup of violets, and it pro- is produced by the efluvia of parts duced as tine a green as spirit of extremely volatile, but different hartshorn; this tincture having from volatile alkali, which, though been changed to a red, by the affu- sooner produced, are more slowly sion of a few drops of aqua-fortis, diffipated, since the fetor generally became again blue, upon pouring continues longer than the alkalef. into it some more of the distilled cence. Alkalescence may, how. liquor. The liquor that distilled ever, be sometimes connected with the five following days, gave the a slight fetor ; and, on the contrasame indications of an alkali. As ry, extreme fetor may subfift withthe distillation entirely ceased after out alkalescence. This is a con. this time, I broke the alembic, and formation of the difference between found juft such a refiduum as be. the fetid and alkaline particles, fore, but under it there was a small which the ingenious Dr. Pringle portion of liquor, reduced to the has demonstrated by another arguconfiftence of syrup, which retain- ment; he observes, that the exha. cd somewhat of analkaline quality, lations of fresh urine are not perbut fo weak, that having exposed nicious, though they contain more it about twelve hours in a window alkali than any substance in a state where the heat of the air was equal of putrefaction, the odour of which to about ten degrees of Reaumur's is pernicious in the highest degree. scale, the alkali totally disap- Putrid effluvia, therefore, are of a peared.

different nature from alkaline falt. 13. This effervescence, and 16. This being the fact, it fol. power of changing fyrup of violets lows that a volatile alkali is not green, proves that putrescent hu. a necessary product of putrefaction, mours form a true alkali, which and that the degree of alkalescence exhales with a very night heat. I is not equal to that of putrefaction; would have made the experiment but that, with respect to vegetable upon the syrup of violets with the substances, natural falts, if mixed putrid humours themselves, but the with oil, become volatile by means opacity of the serum, the red co- of putrescence, though in animal lour of the blood, and the yellow. bodies alkali commences by the ac. ness of the bile, would have ren. tion of the bowels, where envelop. dered it doubtful.

ed with other principles, it becomes 14. As the residuum left in the perfect, or manifests itself by pualembic after distillation, though trefaction; and that for this reanot alkalefcent, is extremely fetid, son, putrefaction engenders a quanit is evident that though the alkali tity of alkali more confiderable in may disengage and exalt this fetor, proportion as it finds in putrescent and render it more penetrating, it bodies more falts, and other ele. is not the productive cause of it, ments, capable, by mixing with because the fetor remains when the falts, of communicating to them alkali is departed.

an alkalescent volatility. Upon

the

the whole, if it is considered, ift, falts, is least subject to putrefacThat acescent plant"; plants that tion; and when it is become puyield an acid in distillation, yield trid, its eflluvia is less hurtful than very little of it when they are con- the effu via of any other humour, verted into blood or humours by which can be attributed only to the the actions of the folids in an ani. abundance of the pre-existing falts, mal body; that they putrify al. and the ftrength of the alkali that most immediately, and yield in is formed out of them. diftillation, instead of an acid, an 17. The urine of a person in alkali, in a great quantity ; 2dly, health will not become putrid in That an alkali is sooner brought less than three days, so as to effer. off by distillation from putrified vesce with acids; but the urine of substances than others. 3dly, That a person fick of a putrid fever, will almost all falts are destroyed by become so putrid as to produce the action of the bowels, and pu. that effect in four and twenty trescence, and that no alkali is hours. The blood of a person so disfound in the ashes of bodies con. eased will also thew signs of alkaleffumed by fire ; and, 4thly, That cence much sooner than the blood the humours which abound with of a person in pleurisy. These salts, particularly the urine, afford particulars, however, belong to the greatest quantity of alkali, af- another class of experiments, ter putrefaction; I shall be jufti- which I referve till a future opfied in adopting the opinion of the portunity, and in which, after an chymists, who Tuppose that volatile examination of the morbific husalts owe their origin to other salts, mouts, and a comparison of the which are thus changed, by the phenomena which they exhibit action of the bowels in animal bus with each other, I Thall endeavour dies, by putrefaction, and by fire, to deduce such consequences as may and that, totally lofing their ori. faciliate the discovery of the causes ginal form, they become alkalies. of diseases, explain their natures, Upon this fuppofition it will be and direct the method of cure. easy to conceive how volatile falts refift putrefaction, as well as salts of other kinds, although putrefaction produces them. The quan. Experiment on the heat that may be tity of alkaline falts produced by caused by the rays of the sun res putrefaction, is indeed in propor- flected from the moon.

By M. De tion to the quantity of natural falts la Hire, the fon. From the Me. pre-existing in the patrifying sub- moirs of the Royal Academy of Itances'; but as thele falts are not Sciences at Parisi fufficient to prevent putrefaction, it is not furprifing that the alkali I number of perfons attribute to which refulis, cannot arreft its progress. If the natural salts had been the moon several qualities, withAtill more abundant, there is realon out producing reasons founded on to think that they might have re- good experiments. I shall not enter tarded its effects; for urine, which into a detail of those qualities, contains the greatest quantity of having remarked, that most of those

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