l66 PHILOSOPHICAL TRANSACTIONS. [aNNO 1771. 



on those particles which have been on the surface, without any strong cohesion 

 with the substance. In the further progress of putrefaction, tlie matter involv- 

 ing the alkali, or forming it, is intermixed, and in cohesion with the solid par- 

 ticles of the substance, and is by these means retained till the alkali is come to 

 its purer state. Towards the end of putrefaction, the cohesion of the particles 

 being almost entirely taken off, the volatile alkali is carried off before it can go 

 through all its states. 



If it is therefore true, that the volatile alkali is essential to, or at least always 

 present in putrefaction, it seems to follow, that the alkalies never can be used 

 in living bodies as antiseptics,* for setting aside their stimulating quality, which 

 must prevent their use in most of the putrid diseases, they would increase the 

 morbific matter, by being intimately mixed by circulation with phlogistic matter, 

 which they find in abundance in such bodies. It has been objected to this that 

 the exhalation of stale urine, though showing a great quantity of volatile alkali, 

 is inoffensive to health i-j- and that some persons have tak^n the volatile alkali in 

 very great quantity, without its bringing on a putrid disease : ;}: but there are 

 however some examples,^ where it has been hurtful. It is urged further, that 

 a person, being only for a short time exposed to really putrid exhalations, may 

 be infected with putrid diseases; and therefore that this effect of putrid exhala- 

 tions does not depend on the volatile alkali, as it may be taken pure, in very 

 large doses, without producing such eff^ects. To this I reply, by an analogous 

 instance ; a small quantity of ferment will bring on fermentation in a large mass 

 of fermentable matter, and yet as much acid as could be obtained from the fer- 



* It appears very difficult to account for the antiseptic power of the volatile alkali, and other salts, 

 on dead animal substances : I once thought, that as the ammoniac salt, nitre, &c. bring down the 

 thermometer several degrees, perhaps all these salts acted by instantly absorbing the heat produced 

 by the beginning intestine motion ; and that, as a certain degree of warmth is necessary to putrefac- 

 tion, in preventing this degree from coming on, it might hinder the whole operation. To see by 

 experiment how far this might be true, I put into phials a certain quantity of water, with that pro- 

 portionate quantity of alkalies, fixed and volatile, sal ammoniac, &c. which Sir John Pringle had 

 found (Append, p. l6, 17) to be antiseptic; and in one as much pure water as a standard. I stopped 

 every one of them with a cork, in which I had made a hole for a thermometer of Fahrenheit. I ex- 

 posed all these phials to the same heat; Sir John had used about 112°; but I found, that both 

 those with the salts, and that without it, marked the same degree of heat ; and that therefore the 

 absorption of heat can by no means be the reason of the putrefaction being stopped. May this phe- 

 nomenon not depend on the salts penetrating the body, and giving to the particles more puncta con- 

 tactus, according to their greater or less affinity.' And may not these salts, in augmenting cohesion, 

 hinder the fluids from separating themselves from one another, and in consequence prevent intestine 

 motion ? Is this not somewhat confirmed by the action of astringents ? and by the most powerful 

 actions of metallic salts, as being of the greatest specific gravity ? — Orig. 



f Sir J. Pringle, Append, p. 7. — Orig. + Id. ibid. p. t)2.— Orig. 



§ Huxham nn the sore throat, p. 67, 6'8. Ejusd. Es-ay on Fevers, p. 118, edit. 5,— Orig. 



