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sensible perspiration increases and occasions this coolness. It is certain that much swimming is the means of stopping a diarrhea, and even of producing a constipation. With respect to those who do not know how to swim, or who are affected with a diarrhea at a season which does not permit them to use that exercise, a warm bath by cleansing and purifying the skin, is found very salutary, and often effects a radi. cal cure. I speak from my own experience, frequento ly repeated, and that of others to whom I have recommended this.

You will not be displeased if I conclude these hasty remarks by informing you, that as the ordinary method of swimming is reduced to the act of rowing with the arms and legs, and is consequently a laborious and fatiguing operation when the space of water to be crossed is considerable; there is a method in which a swimmer may pass to great distances with much facility by means of a sail. This discovery I fortunately made by accident, and in the following manner:

When I was a boy I amused myself one day with flying a paper kite; and approaching the bank of a pond which was near a mile broad, 'I tied the string to a stake, and the kite ascended to a very considerable height above the pond, while I was swimming. In a little time, being desirous of amusing myself with my kite, and enjoying at the same time the pleasure of swimming, I returned; and loosing from the stake the string with the little stick which was fastened to it, went again into the water, where I found, that lying on my back, and holding the stick in my hands, I was drawn along the surface of the water in a very agreeable manner. Having then engaged another boy to carry my clothes round the pond to a place which I pointed out to him on the other side, I began to cross the pond with my kite, which carried me quite over without the least fatigue, and with the greatest pleasure imaginable. I was only obliged occasionally to halt a little in my course, and resist its

progress, when it appeared that, by following too quick, I lowered the kite to much ; by doing which occasionally I made it rise again. I have never since that time practised this singular mode of swimming, though I think it not impossible to cross in this manner from Dover to Calais. The packet-boat, however, is still preferable.



London, July 28, 1768.

I GREATLY approve the epithet you give, in your letter of the 8th of June to the new method of treating the small-pox, which you call the conic or bracing method; I will take occasion, from it, to mention a practice to which I have accustomed myself. You know the cold bath has long been in vogue here as a tonic ; but the shock of the cold water has always appeared to me, generally speaking, as too vio. lent; and I have found it much more agreeable to my constitution to bathe in another element, I mean cold air. With this view I rise early almost every morning, and sit in my chamber without any clothes what ever, half an hour or an hour, according to the season, either reading or writing. This practice is not in the least painful, but, on the contrary, agreeable ; and if I return to bed afterwards, before I dress myself, as sometimes happens, I make a supplement to my night's rest

of one or two hours of the most pleasing sleep that can be imagined. I find no ill consequences whatever resulting from it, and that at least it does not injure my health, if it does not in fact contribute much to its preservation. I shall therefore call it for the future a bracing or tonic bath.

March 10, 1773.

I shall not attempt to explain why damp clothes occasion colds, rather than wet ones, because I doubt the fact; I imagine that neither the one nor the other contribute to this effect, and that the causes of colds. are totally independent of wet and even of cold. I propose writing a short paper on this subject, the first leisure moment I have at my disposal. In the mean uime I can only say, that having some suspicians that the common notion, which attributes to cold the property of stopping the pores and obstructing perspiration, was ill-founded, I engaged a young physician, who is making some experiments with Sanctorius's balance, to estimate the different proportions of his perspiration, when remaining, one hour quite naked, and another warmly clothed. He pursued the experiment in this alternate manner for eight hours successively, and found his perspiration almost double during those hours in which he was naked.

R 2




YOUR observations on the causes of death, and the experiments which you propose for recalling to life those who appear to be killed by lightnings, demonstrate equally your sagacity and humanity. It appears that the doctrines of life and death, in general, are yet but Jittle understood.

A toad, buried in sand, will live, it is said, until the sand becomes petrified ; and then, being inclosed in the stone, it may still live for we know not how many ages. The facts which are cited in support of this opinion, are too numerous and too circumstantial not to deserve à certain degree of credit. As we are accustomed to see all the animals with which we are acquainted eat and drink, it appears to us difficult to conceive how a toad can be supported in such a dungeon. But if we reflect, that the necessity of nourishment, which animals experience in their ordinary state, proceeds from the continual waste of their substance by perspiration : it will appear less incredible that some animals in a torpid state, perspiring less because they use no exercise, should have less need of aliment; and that others, which are covered with scales or shells, which stop perspiration, such as land and sea turtles, serpents, and some species of fish, should be able to subsist a considerable time without any nourishment whatever. A plant, with its flowers, fades and dies immediately, if exposed to the air without having its roots immersed in

a humid soil, from which it may draw a sufficient quan. tity of moisture, to supply that which exhales from its substance, and is carried off continually by the air. Perhaps, however, if it were buried in quicksilver, it might preserve, for a considerable space of time, its vegetable life, its smell and colour. If this be the case, it might prove a commodious method of transporting from different countries those delicate plants which are unable to sustain the inclemency of the weather at sea, and which require particular care and attention.

I have seen an instance of common flies preserved in a manner somewhat similar. They had been drown. ed in Madeira, wine, apparently about the time when it was bottled in Virginia, to be sent to London. At the opening of one of the bottles, at the house of a friend where I was, three drowned flies fell into the first glass which was filled. Having heard it remarked that drowned flies were capable of being revived by the rays of the sun, I proposed making the experi. ment upon these. They were therefore-exposed to the sun, upon a sieve, which had been employed to strain them out of the wine. In less than three hours two of them began by degrees to recorer life. They commenced by some convulsive motions in the thighs, and at length they raised themselves upon their legs, wiped their eyes with their fore feet, beat and brushed their wings with their hind feet, and soon after began to fly, finding themselves in Old England, without knowing how they came thither. The third continued lifeless until sunset, when, losing all hopes of him, he was thrown away.

I wish it were possible, from this instance, to invent a method of embalming drowned persons, in such a manner that they might be recalled to life at any period, however distant; for having a very ardent desire to see and observe the state of America an hun. dred years hence, I should prefer to an ordinary death, the being immersed in a cask of Madeira wine, with a few friends, until that time, then to be recalled to life by the solar warmth of my dear country. But since,

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