In Answer to the preceding.

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 twenty-two years; which account I sent to Mr. W. V. of your town, and have no copy. If I remember right, the number exceeded eight 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 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 will 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 [41], 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. FRANKLIN.