Poplar Forest Aug. 17. 11. Dear Sir I write to you from a place, 90. miles from Monticello, near the New London of this state, which I visit three or four times a year, & stay from a fortnight to a month at a time. I have fixed myself comfortably, keep some books here, bring others occasionally, am in the solitude of a hermit, and quite at leisure to attend to my absent friends. I note this to shew that I am not in a situation to examine the dates of our letters, whether I have overgone the annual period of asking how you do? I know that within that time I have received one or more letters from you, accompanied by a volume of your introductory [struck: letters] lectures, for which accept my thanks. I have read them with pleasure and edification, for I acknolege facts in medecine, as far as they go, distrusting only their extension by theory. Having to conduct my grandson through his course in Mathematics I have resumed that study with great avidity. It was ever my favorite one. We have no theories there, no uncertainties remain on the mind; all is demonstration & satisfaction. I have forgotten much, and recovered it with more difficulty than when in the vigor of my mind, I originally acquired it. It is wonderful to me that old men should not be sensible that their minds keep pace with their bodies in the progress of decay. Our old revolutionary friend, Clinton, for example, who was a hero, but never a man of mind, is wonderfully jealous on this head. He tells eternally the stories of his younger days, to prove his memory. As if memory and reason were the same faculty. Nothing betrays imbecility so much as the being insensible of it. Had not a conviction of the danger to which an unlimited occupation of the Executive chair would expose the republican constitution of our government made it conscientiously a duty to retire when I did, the fear of becoming a dotard and of being insensible of it, would of itself have resisted all solicitations to remain. I have had a long attack of rheumatism, without fever, & without pain while I kept myself still. A total prostration of the muscles of the back, hips, & thighs deprived me of the power of walking, and leaves it still in a very impaired state. A pain, when I walk, seems to have fixed itself [2] in the hip, and to threaten permanence. I take moderate rides without much fatigue: but my journey to this place, in a hardgoing gig, gave me great sufferings, which I expect will be renewed on my return, as soon as I am able. The loss of the power of [struck: nothing] taking exercise would be a sore affliction to me. It has been the delight of my retirement to be in constant bodily activity, looking after my affairs. It was never damped, as the pleasures of reading are, by the question of cui bono? For what object? I hope your health of body continues firm. Your works show that of your mind. The habits of exercise, which your calling has given to both, will tend long to preserve them. The sedentary character of my public occupations sapped a constitution naturally sound and vigorous, and draws it to an earlier close. But it will still last quite as long as I wish it. There is a fulness of time when men should go, & not occupy too long the ground to which others have a right to advance. We must continue, while here, to exchange occasionally our mutual good wishes. I find friendship to be like wine, raw when new, ripened with age, the true old man's milk, & restorative cordial. God bless you & preserve you through a long & healthy old age. Th: Jefferson [address leaf: ] free Th: Jefferson Free Doctr. Benjamin Rush Philadelphia