Dolæus upon the cure of the gout by milk-diet / To which is prefixed, an essay upon diet

by Johann Doläus; William Stephens

Fermentation is a Change in Vegetables by Means of some intestine Motion, the Effect whereof is, that in Distillation there arises a volatile inflammable Liquor, capable of mixing with Water, commonly called Spirits; or if the Fermentation be so managed as to produce Vinegar, thence arises in Distillation a watry, thin, acid Liquor, capable of extinguishing Fire. I have here only mentioned the Effects of Fermentation; what this intestine Motion is, or its Cause, I do not pretend to describe, because I do not know it: Its Effects are very well known to be either a vinous or an acetous Liquor, and they are producible from all Vegetables, and from Vegetables only; for all the Art yet known will never gain such Spirits either from Fossils or Animals: Putrefaction, Digestion, and Effervescence are all done by intestine Motions, but will neither produce Wine nor Vinegar; so that in this Light Fermentation is confined to Vegetables.

It needs no very deep Enquiry into the History of Fermentation, to know, that in Wine (by which Name I understand all fermented Vegetable Liquor, Ale, Beer, Mead, and all artificial Wines, as well as that made from the Grape) the Spirituous Parts of the Vegetable are so volatilized and loosened, that very small Heat raises them from the other Parts of the Liquor, even many fly off upon being exposed to the Air: The viscid, oily, and glutinous Parts of Vegetables are so broke and separated, and the Spheres of their mutual Attractions so diversified, that they are no longer retained. Before Fermentation, the longer you boil the Decoction of any Vegetable, its oily and spirituous Parts are more concentrated, and little besides Water, and some essential Oyl goes away; after Fermentation the Spirit goes away, and the Water remains: This is commonly known to Brewers and Distillers.

What is next observable in this Change is, that the essential Salt is thrown from the Body of the Liquor thus fermented, and adheres to the Side of the Vessel wherein the Liquor is deposited, and crystallizes into Tartar. In Vinegar this Salt is kept in the Mass of the Fluid (the Oyl being thrown off) where uniting with the aqueous and spirituous Parts, it turns sowre, and becomes Vinegar by Means of that Fermentation. After this no Tartar can be generated from it, nor any inflammable Spirit obtained; but on the contrary, a watry, poor, acid Liquor, capable of extinguishing Fire, rises first from the Still. In Wine, the volatile Salt and Oyl of the Vegetable are attenuated and reduced into one Spirit; Vinegar is the essential Salt of Wine made more acid by a new Fermentation, and intimately mixed with the watry and spirituous Parts of the same.

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.