After this, I found that Mr. Lavoisier had completely discovered the same thing, though his apparatus being more complex, and less accurate than mine, he concluded that more of the air discharged from the calces of metals was immiscible with water than I found it to be. It appeared to me that I had never obtained fixed air more pure.
It being now pretty clearly determined, that common air is made to deposit the fixed air which entered into the constitution of it, by means of phlogiston, in all the cases of diminished air, it will follow, that in the precipitation of lime, by breathing into lime-water the fixed air, which incorporates with lime, comes not from the lungs, but from the common air, decomposed by the phlogiston exhaled from them, and discharged, after having been taken in with the aliment, and having performed its function in the animal system.
Thus my conjecture is more confirmed, that the cause of the death of animals in confined air is not owing to the want of any pabulum vitæ, which the air had been supposed to contain, but to the want of a discharge of the phlogistic matter, with which the system was loaded; the air, when once saturated with it, being no sufficient menstruum to take it up.
The instantaneous death of animals put into air so vitiated, I still think is owing to some stimulus, which, by causing immediate, universal and violent convulsions, exhausts the whole of the vis vitæ at once; because, as I have observed, the manner of their death is the very same in all the different kinds of noxious air.
To this section on the subject of diminished, and noxious air, or as it might have been called phlogisticated air, I shall subjoin a letter which I addressed to Sir John Pringle, on the noxious quality of the effluvia of putrid marshes, and which was read at a meeting of the Royal Society, December 16, 1773.
This letter which is printed in the Philosophical Transactions, Vol. 74, p. 90. is immediately followed by another paper, to which I would refer my reader. It was written by Dr. Price, who has so greatly distinguished himself, and done such eminent service to his country, and to mankind, by his calculations relating to the probabilities of human life, and was suggested by his hearing this letter read at the Royal Society. It contains a confirmation of my observations on the noxious effects of stagnant waters by deductions from Mr. Muret's account of the Bills of Mortality for a parish situated among marshes, in the district of Vaud, belonging to the Canton of Bern in Switzerland.
To Sir JOHN PRINGLE, Baronet.
DEAR SIR,
Having pursued my experiments on different kinds of air considerably farther, in several respects, than I had done when I presented the last account of them to the Royal Society; and being encouraged by the favourable notice which the Society has been pleased to take of them, I shall continue my communications on this subject; but, without waiting for the result of a variety of processes, which I have now going on, or of other experiments, which I propose to make, I shall, from time to time, communicate such detached articles, as I shall have given the most attention to, and with respect to which, I shall have been the most successful in my inquiries.
Since the publication of my papers, I have read two treatises, written by Dr. Alexander, of Edinburgh, and am exceedingly pleased with the spirit of philosophical inquiry, which they discover. They appear to me to contain many new, curious, and valuable observations; but one of the conclusions, which he draws from his experiments, I am satisfied, from my own observations, is ill founded, and from the nature of it, must be dangerous. I mean his maintaining, that there is nothing to be apprehended from the neighbourhood of putrid marshes.
I was particularly surprised, to meet with such an opinion as this, in a book inscribed to yourself, who have so clearly explained the great mischief of such a situation, in your excellent treatise on the diseases of the army. On this account, I have thought it not improper, to address to you the following observations and experiments, which I think clearly demonstrate the fallacy of Dr. Alexander's reasoning, indisputably establish your doctrine, and indeed justify the apprehensions of all mankind in this case.