Johannes Dolæus - Dolæus upon the cure of the gout by milk-diet

The Spirit produced from the Distillation of Wine is a Liquor of such active Parts, and capable of effecting such Changes in animal Bodies, that it ought to be retained entirely to Medicine; but since it is too much used in Diet, it may be proper to remember it under that Head.

I must take Notice of one other Change in Vegetables, and that is what they undergo by Putrefaction, because it Approaches somewhat to animal Digestion, and gives us some Sort of Notion of the Manner of converting vegetable into animal Substances.

It is very well known, that if a Quantity of green recent Vegetables be heaped up together, and pressed down, they will in a little Time begin to heat in the Middle, and in the Course of eight or ten Days will have passed by Degrees to a violent Heat, so as sometimes to flame and burn away; this Mass acquires a putrid, cadaverous, feculent Taste and Smell, and turns into a soft, pappy Substance, resembling human Excrement in Scent, and putrified Flesh in Taste; and by all the Tryals that can be made, gives us no mark of vegetable Substance, but is entirely turned into an animal one: For upon Distillation it yields a Water of an urinous Scent; a white, volatile, dry, alkaline Salt; a volatile, alkaline, oily Salt; and a thick fetid Oyl, all the same that are producible from animal Substances; and lastly, (which is the nicest Criterion between vegetable and animal Substances) if the Remainder be calcined in an open Fire, it will not yield the least Particle of fixed Salt, which all Vegetables whatsoever are known to do.

All Vegetables whatever are subject to this Putrefaction (and indeed Animals too) and all specifick Differences are destroyed by it: It is evidently caused by Fire itself collected or included within the subject; and seems to be a general Law of Nature, wisely established, to produce wonderful Changes in the World, and to prevent the Indolence of Matter; this active Principle or Medium giving an easy and reciprocal Transition of vegetable into animal Substances, and of animal into vegetable. I think it cannot be out of the Way here to observe, that the Change which the Aliment suffers in the human Body, is in some Measure reducible to this; for if a Man should live entirely upon acid Vegetables, acid Bread, and Fruits, drink Rhenish Wine, no Part of his Body or Juices would, upon Distillation, or other Tryal, yield the least Portion of an acid or fixed Salt, but constantly a volatile Alkali. There cannot indeed be supposed any perfect Putrefaction in the Bodies of Animals; for so soon as any Thing contained therein tends this Way, it is discharged as Excrement; all the Acids of the Aliment are subdued by the vital Powers of Animals, and converted into volatile Salts of an alkaline Nature; without an actual or real Putrefaction, yet by an Operation nearly approaching thereto: If these Salts were not discharged, before Putrefaction (as by examining the Excrement it appears they are) they must produce such terrible Effects as would immediately destroy the Animal.

In examining vegetable Substances as Food, we must consider them as eaten Raw, as prepared by the Arts of Cookery, and as subjected to Fermentation. In the first Case they are sometimes the Food of Men, always of Animals that we feed upon; in the others the Food of Men alone.

Raw Vegetables that become Parts of Animals, are bruised, ground, and comminuted by the proper animal Organs, and mixed with animal Juices in their Passage. By this Means their Juices are expressed; such of them as are capable of mixing with Water naturally, or by the intermediate Assistance of the Bile, are formed into one common fluid Mass or Chyle, which constitutes the first Nourishment of Animals; whence the Blood, Serum, Lymph, and other animal Juices are formed. From what was said before, this appears to be the Water, impregnated with the essential Salt, the Spirit, some Portion of its essential Oyls, mixed with the Water by Means of the Salt and the Bile; these by the vital Powers are formed into a white Liquor, which is the Chyle, not unfitly represented in the common making of Emulsions from oily Seeds. The Chyle still retains its vegetable Nature, and somewhat specifick to the Vegetable it came from; but when it hath been circulated several Times thro’ the Body, and thoroughly mixed with the Juices thereof, it acquires animal Properties; vegetable and animal Juices are pretty near of the same specifick Gravity, and consequently fit to repair each other; the different Impulses of Heat and Motion, with due Mixture, create the Difference; though this will always hold true, that an animal Body constantly repaired from vegetable Juices, cannot have so strong a tendency to a putrescent alkaline State, as a Body constantly repaired from animal Juices, already disposed to that State.

The common Effects of the Art of Cookery upon Vegetables, will be understood by what happens in the Decoction of Plants. In boiling any Plant, its most sublime fluid Part flies off, and indeed it is incapable of bearing a greater Heat than that of the Summer Sun, the Salts of the Plant are dissolved in the Water, and its thicker and grosser Oyl rises to the Top, like a fat Scum; so long as the Plant retains any Taste or Odour, change the Water as often as you please, there will constantly arise a fat, odorous, viscous, inflammable and frothy Matter, which can be no other than the Oyl of the Plant loosened from the Salts. In Proportion then, as the Salts are dissolved in the boiling Water, the Oyl attenuated, as it must be before it can be so far specifically lighter as to arise to the Top, we are to judge how far the Art of Cookery is serviceable in the Preparation of vegetable Diet.

From what was said before in relation to Fermentation, it is plain that the vegetable Oyls are much volatilized, rendred more active, and separated from the Salts; upon this Account it is, that they are endowed with an inebriating Quality, which is confined entirely to Wines, for no other Substance hath that Quality. No one was ever drunk with eating Grapes, or drinking Must or Wort before Fermentation. The stupifying Quality of Poppy, Henbane, Mandrakes, Nightshade, and other Plants of that Class, is very different from the Effects of Wine or its Spirit. The chief Effect of Fermentation, in Regard to Diet, is supposed to consist in rendring vegetable Substance less difficult to be overcome by the Action of animal Organs and Mixtures, and easier to the digestive Powers; but there are other good Effects not so commonly thought of; fermented vegetable Substance is very little subject to Putrefaction, and is a great Preservative against it. By the styptick Power that the Spirit is endowed with, the Tone of the Fibres is increased in Digestion, their Force enlarged, and consequently their Action greater upon the vegetable Parts, and a larger Quantity of animal Juices mixed with them; and it is no difficult Matter to imagine, that the inward Heat of an human Body should draw forth the Spirit of fermented Liquors.

The Parts of Vegetables most used in Food, are the Seeds of Plants, our common Bread and Drink being made from them: These, by what was said before, contain the most elaborated Juices, the greatest Quantity of fine Oyl and Spirit, and are consequently most fit for Nourishment; several Fruits are eaten Raw, because their Juices are concocted to the utmost Degree of Perfection, and contain, in greatest Quantity, the finest and most elaborated vegetable Oyl, mixed with the essential Salts peculiar to each, which would be lost in Decoction: But the coarser Parts of Vegetables, as Roots, Leaves, Stalks, unripe Fruits, and Flowers, require the Arts of Cookery to be exercised upon them, to render them more easily subject to the animal Powers, and assimilable to their Juices.

I design not to enter into the several specifick Differences of Vegetables, I hope I have said enough to explain their general Nature, and how they become reducible into animal Substances; I shall next consider these Substances in the same Manner.