To John Perkins
Printed in Benjamin Franklin, Experiments and Observations on Electricity (London, 1769), pp. 195-6.
Philadelphia, Aug. 13, 1752
Sir,

I received your favour of the 3d instant. Some time last winter I procured from one of our physicians an account of the number of persons inoculated during the five visitations of the small-pox we have had in 22 years; which account I sent to Mr. W[illiam] V[assall], of your town, and have no copy. If I remember right, the number exceeded 800, and the deaths were but 4. I suppose Mr. V[assall] will shew 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 before, in the common way.

I shall be glad to see what Dr. Douglass may write on the subject. I have a French piece printed at Paris 1724, entitled, Observations sur la Saignée du Pied, et sur la Purgation au commencement de la Petite Verole, & Raisons de doubte 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’ll send 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 amusements. Whatever I have wrote of that kind, are really, as they are entitled, but Conjectures and Suppositions; which ought always to give place, when careful observation militates against them. I 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 disagree with my pre-conceived notions.

I am sorry to hear that the number of your inhabitants decreases. I 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 favourable opinion you express of my writings, may, you see, occasion you more trouble than you expected from, Sir, Yours, &c.

B.F.

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