47. TO JOSIAH AND ABIAH FRANKLIN1

Philadelphia, September 6, 1744.

HONOURED FATHER AND MOTHER,

I apprehend I am too busy in prescribing and meddling in the doctor's sphere, when any of you complain of ails in your letters. But as I always employ a physician myself, when any disorder arises in my family, and submit implicitly to his orders in every thing, so I hope you consider my advice, when I give any, only as a mark of my good will, and put no more of it in practice than happens to agree with what your doctor directs.

Your notion of the use of strong lye I suppose may have a good deal in it. The salt of tartar, or salt of wormwood, frequently prescribed for cutting, opening, and cleansing, is nothing more than the salt of lye procured by evaporation. Mrs. Stevens's medicine for the stone and gravel, the secret of which was lately purchased at a great price by the Parliament, has for its principal ingredient salt, which Boerhaave calls the most universal remedy. The same salt intimately mixed with oil of turpentine, which you also mentioned, make the sapo philosophorum, wonderfully extolled by some chemists for like purposes. It is highly probable, as your doctor says, that medicines are much altered in passing between the stomach and bladder; but such salts seem well fitted in their nature to pass with the least alteration of almost anything we know; and, if they will not dissolve

1 From "The Works of Benjamin Franklin." Philadelphia: (Duane) 1817, Vol. VI, p. 6. — ED.

gravel and stone, yet I am half persuaded that a moderate use of them may go a great way towards preventing these disorders, as they assist a weaker digestion in the stomach, and powerfully dissolve crudities such as those which I have frequently experienced. As to honey and molasses, I did not mention them merely as openers and looseners, but also from conjecture, that, as they are heavier in themselves than our common drink, they might when dissolved in our bodies increase the gravity of our fluids, the urine in particular, and by that means keep separate and suspended therein those particles, which, when unused, form gravel, &c.

I will inquire after the herb you mention. We have a botanist here, an intimate friend of mine, who knows all the plants in the country. He would be glad of the correspondence of some gentlemen of the same taste with you, and has twice, through my hands, sent specimens of the famous Chinese ginseng, found here, to persons who desired it in Boston, neither of whom has had the civility to write him a word in answer, or even to acknowledge the receipt of it, of which please to give a hint to brother John.

We have had a very healthy summer and a fine harvest; the country is filled with bread; but, as trade declines since the war began, I know not what our farmers will do for a market. I am your affectionate and dutiful son,

B. FRANKLIN.

1 John Bartram. — ED.

48. TO JOHN FRANKLIN, AT BOSTON1

PHILADELPHIA, [Mar. 10,] 1745.

Our people are extremely impatient to hear of your success at Cape Breton. My shop is filled with thirty inquirers at the coming in of every post. Some wonder the place is not yet taken. I tell them I shall be glad to hear that news three months hence. Fortified towns are hard nuts to crack; and your teeth have not been accustomed to it. Taking strong places is a particular trade, which you have taken up without serving an apprenticeship to it. Armies and veterans need skilful engineers to direct them in their attack. Have you any? But some seem to think forts are as easy taken as snuff. Father Moody's prayers look tolerably modest. You have a fast and prayer day for that purpose; in which I compute five hundred thousand petitions were offered up to the same effect in New England, which added to the petitions of every family morning and evening, multiplied by the number of days since January 25th, make forty-five millions of prayers; which, set against the prayers of a few priests in the garrison, to the Virgin Mary, give a vast balance in your favour.

If you do not succeed, I fear I shall have but an indifferent opinion of Presbyterian prayers in such cases, as long as I live. Indeed, in attacking strong towns I should have more dependence on works, than on faith; for, like the king

1 This letter is undated, but from Franklin's ecclesiastical mathematics it would appear to have been written on the tenth of March. His calculation of 500,000 inhabitants of New England is perhaps 100,000 in excess of the actual population. The news of the fall of Louisburg came at about the time that Franklin predicted. — ED.

dom of heaven, they are to be taken by force and violence; and in a French garrison I suppose there are devils of that kind, that they are not to be cast out by prayers and fasting, unless it be by their own fasting for want of provisions. I believe there is Scripture in what I have wrote, but I cannot adorn the margin with quotations, having a bad memory, and no Concordance at hand; besides no more time than to subscribe myself, &c.

B. FRANKLIN.

SIR,

49. TO CADWALLADER COLDEN

PHILADELPHIA, August 15, 1745.

I received your favour of the 20th past, with your medical piece enclosed, the reading of which gave me a great deal of pleasure. I showed it to our friend Mr. Bartram, who carried it home, and, as he since tells me, is taking a copy of it. His keeping of it for that end has prevented my showing it to any other gentleman as you desired, and hitherto prevented my writing to you upon it, as I intended. But, lest you should conclude me the very worst correspondent in the world, I shall delay no longer giving you some thoughts, that occurred to me in reading of it, choosing rather to be blamed for not writing to the purpose, than for not writing at all.

I am extremely pleased with your doctrine of the absorbent vessels intermixed with the perspiratory ducts, both on the external and internal superficies of the body. After I had read Sanctorius, I imagined a constant stream of the perspirable matter issuing at every pore in the skin.

But then I

was puzzled to account for the effects of mercurial unctions for the strangury, sometimes occasioned by an outward application of the flies, and the like; since whatever virtue or quality might be in a medicine laid upon the skin, if it would enter the body, it must go against wind and tide, as one may say. Dr. Hales helped me a little, when he informed me, in his Vegetable Statics,' that the body is not always in a perspirable, but sometimes in an imbibing state, as he expresses it, and will at times actually grow heavier by being exposed to moist air. But this did not quite remove my difficulty; since, as these fits of imbibing did not appear to be regular or frequent, a blistering plaster might lie on the body a week, or a mercurial unguent be used a month, to no purpose, if the body should so long continue in a perspirable state. Your doctrine, which was quite new to me, makes all easy; since the body may perspire and absorb at the same time, through the different ducts destined to those different ends.

I must own, however, that I have one objection to the explanation you give of the operation of these absorbents. That they should communicate with the veins, and the perspirants with the arteries only, seems natural enough; but, as all fluids by the hydrostatical law pass equally in all directions, I question whether the mere direction of one of those minute vessels, where it joins with a vein or artery, with or against the stream of blood in the larger vessel, would be sufficient to produce such contrary effects as perspiring and absorbing. If it would, both perspirants and absorbents might proceed from the arteries only, or from the veins only, 1 Stephen Hales (1677-1761), "Vegetable Staticks, or an Account of some Statical Experiments on the Sap in Vegetables." London: 1727. — ED.