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I pass this opportunity without any particulars of my old theme. One thing, however, I must mention, which is, that perhaps my last letters contained something that seemed to militate with your doctrine of the origin, etc. But my design was only to relate the phenomena as they appeared to me. I have received so much light and plea. sure from your writings, as to prejudice me in favour of every thing from your hand, and leave me only liberty to observe, and a power of dissenting when some great probability might oblige me: and if at any time. that be the case, you will certainly hear of it.

I am, Sir, etc.

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FROM BENJAMIN FRANKLIN, ESQ. OF

PHILADELPHIA,
In answer to the preceding.

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Philadelphia, Aug. 13, 1762. SIR, I received your favour of the 3d instant. Some time last winter I procured from one of our physicians an ac. count of the number of persons inoculated during the five visitations of the small-pox we have had in twenty, two years;, which account I sent to Mr. W. V. of your town, and have no copy. If I remember right, the num. per exceeded cight hundred, and the deaths were but four. I suppose Mr. V. will show you the account, if he ever received it. Those four were all that our doctors allow to have died of the small-pox by inoculation, though I think there were two more of the inoculated who died of the distemper: but the eruptions appearing soon after the operation, it is supposed they had taken the infection be. fore, in the common way.

I shall be glad to see what Dr. Douglas may write on the subject. have a french piece printed at Paris, 1724, entitled, Observations sur la saignee du Pied, et sur la Purgation au commencement de la Petite Verole, and Raisons de doute contre l' Inoculation. - A letter of the doctor's is mentioned in it. If he or you have it not, and desire to see it, I will sent it. Please to favour me with the particulars of your purging method, to prevent the secondary fever.

I am indebted for your preceding letter, but business sometimes obliges one to postpone philosophical amuse. ments. Whatever I have wrote of that kind, are really as they are entitled, but conjectures and suppositions; which onght always to give place, when careful observa

tion militates against them. own I have too strong a penchant to the building of hypotheses; they indulge my natural indolence: I wish I had more of your patience and accuracy in making observations, on which, alone, true philosophy can be founded, And, I assure you, nothing can be more obliging to me, than your kind communication of those you make, however they may dis. agree with my pre-conceived notions.

I am sorry to hear that the number of your inhabitants decreases. some time since, wrote a small paper of thoughts on the peopling of countries, which, if I can find I will send you, to obtain your sentiments. The fa. vourable opinion you express of my writings, may, you see, occasion you more trouble than you expected from, Sir, yours, etc.

B. FRANKLIN.

TO BENJAMIN VAUGHAN, ESQ. On the effects of Lead upon the human Con

stitution.

Philadelphia, July 31, 1786. DEAR FRIEND, I recollect that when I had last the pleasure of seeing you at Southampton, now a twelvemouth since, we had some conversation on the bad effects of lead taken inwardly; and that at your request I promised to send you in writing a particular account of several facts I then mentioned to you, of which you thought some good use might be made. I now sit down to fulfil that promise.

The first thing I remeniber of this kind was a general discourse in Boston when I was a boy, of a complaint from North Carolina against New England rum, that it poisoned their people, giving them the dry-belly-ach, with a loss of the use of their limbs. The distilleries being examined on the occasion, it was found, that several of them used leaden still-heads and worms, and the physicians were of opinion, that the mischief was occasioned by that use of lead. The legislature of Massachussets thereupon passed an act, prohibiting, under severe penalties, the use of such still-heads and worms hereafter.

In 1724, being in London, I went to work in the printinghouse of Mr. Palmer, Bartholomew-close, as a compositor. I there found a practice, I had never seen before, of drying a case of types (which are wet in distribution) by placing it sloping before the fire. I found this had the

additional advantage, when the types were not only dried but heated, of being comfortable to the hands working over them in cold weather. I therefore sometimes heated my case when the types did not want drying. But an old workman observing it. advised me not to do so, telling me 1 wight lose the use of my hands by it, as two of our companions had nearly done, one of wliom, that used to earn his guinea a week, could not then make more than ten shillings, and the other who had the dangles, but seven and sixpence. This, with a kind of obscure pain, that I had sometimes felt, as it were, in the bones of my hand when working over the types made very hot, induced me to omit the practice. Biit talking afterwards with Mr. James, a letter founder in the same Close, and asking him if his people, who worked over the little furnaces of melted metal, were not subject to that disorder, he made light of any danger froin the effluvia, but ascribed it to particles of the metal swallowed with their food by slovenly workmen, who went to their meals after handling the metal, without well washing their fingers, so that some of the metalline particles were taken of 'by their bread and eaten with it. This appeared to have some reason in it. But the pain I had experienced made me still afraid of those effluvia.

Being in Derbyshire at some of the furnaces for smelt. ing of lead ore, I was told, that the smoke of those fournaces was pernicious to the neighbouring grass and other vegetables, but I do not recollect to have heard any thing of the effect of such vegetables eaten by animals. It may be well to make the inquiry.

In America I have often observed, that on the roofs of our shingled houses, where moss is apt to grow in northern exposures, if there be any thing on the roof painted with white lead, such as balusters, or frames of dormant windows, etc. there is constantly a streak on the shingles from such paint down to the eaves, on which no moss will grow, but the wood remains constantly clean and free from it. We seldom drink rain - water that falls on our houses; and if we did, perhaps the small quantity of lead descending from such paint night not be sufficient to produce any sensible ill-effect on our bodies. But I have been told of a case in Europe I forget the place, where a whole family was afflicted with what we call the dry-belly.ach, or colica pictorum, by drinking rain-water. It was at a country.seat, which being situated too high to have the advantage of a well, was supplied with water from the leaded roofs. This had been drank several years without mischief, but some young trees planted near the · house growing up above the roof, and shedding their leaves upon it, it was supposed, that an acid in those leaves had corroded the lead they covered, and furnished the water of that year with its baneful particles and qualities,

When I was in Paris with Sir John Pringle in 1767,

he visited La Charité, an hospital particularly famous for the core of that malady, and brought from thence a pamphlet, containing a list of the names of persons, specifying their professions or trades, who had been cured there. I had the curiosity to examine that list, and found, that all the patients were of trades, that some way or other use or work in lead; such as plumbers, glaziers, painters, etc. excepting only two kinds, stone-cntters and soldier's. In them, I could not reconcile it to my notion, that lead was the cause of that disorder.

But on my mentioning it to a plıysician of that hospital, he informed me, that the stone-cutters are continually using melted lead, to fix the ends of iron balustrades in stones; and that' the soldiers liad been employed by painters as labourers in grinding of colours.

This, my dear friend, is all I can at present recollect on the subject. You will see by it, that the opinion of this mischievous effect from lead, is at least above sixty years old; and you will observe with concern how long a useful truth may be known and exist, before it is geuerally received and practised on. I am, ever, yours most effectionately,

B. FRANKLIN.

TO M. DUBOURG, Observations on the prevailing Doctrines of Life

and Death,

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

A toad buried in sand will live, it is said, till the sand becomes petrified: and then, being inclosed in the stone, it may still live for we know not how inany ages. The facts which are cited in support of this opinion are too numerous, and too circumstantial, not to deserve a 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

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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 seaturtles, 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 im. mediately, if exposed to the air without having its root immersed in a humid soil, from which it may draw a suf ficient quantity 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 fife, its smell and colour. If this be the case, it might prove a commodious method of transporting from distant 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 drowned in Madeira wine, apparently about the time when it was bottled in Virginia, to be sent hither (to London). At the opening of one of the bottles, at the house of a friend where I then was, three drowned flies fell into the first glass that was filled. Having heard it remarked that drowned flies were capable of being re. vived by the rays of the sun, 1 proposed making the experiment 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 recover life. They commenced by some convulsive motions of 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 till 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 may be recalled to life at any period, however distant; for having a very ardent desire to see and observe the state of America an hundred years bence, I should prefer to an ordinary death, the being immersed in a cask of Madeira wine, with a few friends till that time, to be then recalled to life by the solar warmth of my dear country! But since in all probability we live in an age too early and too near the infancy of science, to hope to see such an art brought in our time to its perfection, must for the present content myself with the treat, which you are so kind as to promise me, of the resurrection of a fowl or a turkey.cock.

I am, etc.

B. FRANKLIN,

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