eating and drinking, at certain times, should not be absolutely prohibited.

VIII.

AN EXPLANATION OF THE OPERATION UPON THE LAST ACT OF ASSIMILATING THE FOOD.

THERE needs no more than a short and simiple direction about the last act of assimilation; which is the thing intended by the three operations immediately preceding: as this affair rather requires explanation, than any variety of rules.

It is certain, that all bodies have some appetite of assimilating, or turning into their own substance such things as are next them. This is done copiously and briskly by all subtile and pneumatical bodies; as flame, air, and spirits: and but very weakly by those of a gross, tangible substance, which have their appetite of assimilation bound down, and restrained by a stronger appetite of rest, and avoiding of motion.

It is likewise certain that this appetite of assimilation, which we observe to be kept under, and rendered unactive, in gross tangible substances, is still animated, or somewhat released, set free, excited, and at length actuated by heat, or spirit, coming in contact with them. And

this is the only reason why animate bodies do, and inanimate bodies do not assimilate.

Again, it is certain that the harder the consistence of a body is, the greater heat it requires to excite the act of assimilation; but in old age it happens, very disadvantageously, that all the parts grow stubborn, and the heat grows weak: and therefore this stubbornness of the parts must be either mollified, or the heat encreased. But of malaxing the parts we shall presently speak, in particular; and have already proposed many expedients for preventing their hardness. And for the other intention, of increasing heat, we shall lay down a single rule upon the strength of the following axiom.

The act of assimilation, being excited by the mediation of heat, is an extremely subtile and intimate motion, in the small particles of the matters concerned: but such motions are in greatest motion when the local motion ceases; which might otherwise disturb it. For the motion of separation into homogeneous parts; as in milk, where the cream rises, and the thinner parts subside; could never be effected if the milk were kept, though but in a gentle agitation: nor will water, or mixed bodies, putrify whilst they are continued in perpetual local motion.

As, therefore, the act of assimilation is prin

cipally performed in sleep and rest; especially towards the morning, after the distribution has been made of the aliment; we can think of no other rule to answer this intention, than to sleep warm; and towards the morning use such a kind of motion, or put on such a prepared linen bed-gown, as may excite a moderate heat and upon this to sleep again.*

IX.

THE HISTORY OF THE OPERATION FOR MOLLIFYING THE PARTS WHEN THEY BEGIN TO GET DRY OR FOR SUPPLYING AND MALAXING THE BODY.

HAVING already enquired into the internal methods of supplying the body, which proceed by many windings and turnings, in respect both of the aliment and the detention of the spirits; and therefore necessarily operate but slow; we come next to enquire into the external and shorter ways of affecting the same thing.

In the fable of restoring Pelias to youth, Medea preparing for the operation, proposes to cut the old man's body to pieces; and then to boil it with certain simples in a cauldron. But

*The axiom above laid down, and the rule deduced from it, may afford a specimen of the method wherein the author here endeavours, and directs all other enquiries to proceed.

though, literally, some kind of coction may be requisite in such an intention; surely the body need not be cut in pieces for it. And yet some kind of cutting seems necessary, though not with a knife, but the judgment; for as there is a great difference between the consistence of the viscera and other parts, they cannot all be mollified the same way; but regard must be had to each of them respectively; besides what belongs to the general intention of suppling the whole mass of the body of which in the first place.

And if the thing be possible; bathing, anointing, and the like, may conduce thereto. But we must not fondly imagine it performable, from what we see happen in the steeping and macerating of inanimate bodies; whereby they are rendered soft and tender, according to some examples formerly produced: for this operation is more facile upon inanimate bodies, because they attract and suck in fluids; but more difficult in animal bodies, because motion in them tends rather from the center to the circumference.

And therefore, the common emollient baths, in use, are of little service, or rather opposite to this intention; as they rather extract than insinuate; and rather loosen than confirm the texture of the body.

There are three properties required in the baths and unctions designed for this operation,

of duly and substantially supplying the body. 1. The first principal property is, that they consist of such things, as in their whole substance are similar to the body, and the human flesh; and at the same time bland, and nourishing from without. 2. That they have such things mixed with them, as by their subtilty of parts may gain entrance; and so convey and spread the nutritive virtue of the other ingredients along with themselves: and, 3. that they receive some small mixture of such things as are constringent, or strengthening; nor rough or austere, but balmy and cherishing; so that whilst the other two perform their operation, all exhalation from the body may, as much as possible, be prevented; which might otherwise destroy the malaxing virtue; and rather that, by constringing the skin, and closing up the pores, the motion towards the internal parts may be assisted and promoted.

What approaches nearest to the substance of the human body, is warm animal blood; but that conceit of Ficinus for restoring strength to old men, by sucking blood from the arm of a young one, is strangely empty for what nourishes internally, ought by no means to be consubstantial or perfectly homogeneous with the body to be nourished; but of a somewhat lower and subordinate class, that it may be converted: