As to the former, we are to consider, that Fermentation being a Change made in the Cohæsion of the compounding Parts of a Fluid, it is sometimes a longer, sometimes a shorter time before this Alteration is wrought; which variety may proceed either from the different Nature and Constitution of the Ferment, or of the Liquor Fermented, and a great Number of Circumstances besides. So that this Venom may be all the while doing its Work, tho’ the change made by it may not be so considerable as to be sensibly taken Notice of till a long time after.
Nay, it may so happen, that the Ferment being Weak may not raise in the Blood any remarkable Agitation at all, till some accidental Alteration in the Body unluckily gives it an additional Force. As we before observed, how much external Heat concurrs to heighten the Symptoms from the Bite of the Tarantula. And this probably may be the Case of Those in whom this Malignity has not appear’d till Six, or Twelve Months after the Wound.
That we may understand the Reason of the Hydrophobia, it is to be Remarked, that this dread of Water does not come on till the latter end of the Disease, Three or Four Days before Death; that is, not till this preternatural Fermentation in the Blood is come to its Heigth; and as in the Dog, so in the Patient, a great quantity of Fermentative Particles is thrown off upon the Glands of the Mouth and Stomach, as appears by his Foaming at the Mouth, &c.
As also, that this Fear is not from a sight of, or any imaginary appearance in the Water, for if the Vessel be close shut, and the Patient bid to suck thro’ a Quill, as soon as he has tasted, he falls into Anguish and Convulsions, as Dr. Lister observed. It is therefore highly probable, if not certain, that this surprising Symptom proceeds from the intolerable Pain which any Liquor at this time taken induces, partly by hurting the inflamed Membranes of the Fauces in Deglutition; partly by fermenting with these Active Particles discharged by the Blood upon the Stomachic Glands, and thus twitching and irritating the Nervous Membranes; the very memory of which grievous Sence, after it is once felt, is so terrible, that the affected Person chuses any thing rather than to undergo it a second time.
The Effects of this Irritation are manifest in the Convulsions of the Stomach, and frequent Singultus, with which the Patient is continually oppress’d. And we all know by how necessary a kind of Mechanism we do fly from and abhor those things which have proved disagreeable to the Animal Œconomy, to which nothing is so contrary and repugnant as Pain; at the first Approaches of which, Nature Starts and Recoils, tho’ Reason be arm’d with never so much Courage and Resolution to undergo the Shock.
Nor will any Body wonder how this Ferment should cause such Torment, who considers how often, even in Colical Cases, Persons are downright distracted by excessive Pain, from a Cause not unlike to this we are treating of, that is, from a corrosive Ferment in the Bowels, rarefying the Juices there into Flatus, and by this means irritating and stimulating those tender Membranes into Spasmodic and Convulsive Motions.
And indeed Dr. Lister’s Patient told him, that the very swallowing of his own Spittle put him to such Torture in his Stomach, that Death it self was not so Terrible as the Inexpressible Agony.
It may serve both to Illustrate and Confirm this Theory, to take Notice, that not only may (according to these Principles) other Bites besides that of a Dog happen to induce the like Symptoms; thus Malpighi [(78)] relates a Story of a Mother made Hydrophoba by the Bite of her Epileptic Daughter; but that there are other Cases, without any Bite at all, which are attended with an Hydrophobia.
Thus Schenkius [(79)], Salmuth [(80)] and others have observ’d a Dread of Water, without any Suspicion of a Bite, from Malignant Fevers. Now in These there is doubtless a Hot, Putrid Ferment in the Blood; and it is no wonder if Part of it be discharged upon the Throat and Stomach, which we do evidently find in these Distempers to be more particularly affected by It, especially towards the latter End, from the Aphthæ, Singultus, and the like usual Symptoms of a fatal Malignity.
Nay, Hippocrates [(81)] himself seems more than once to have remarked something like this Symptom in Fevers, and to call those who were thus affected Βραχυπόται, or little Drinkers; for I cannot assent to Dr. Lister, (tho’ Cælius Aurelianus be on his side) who thinks that the Βραχυπόται are ὑδροφόβοι, from the Bite of a Mad Dog; as well for other Reasons, as because Plutarch [(82)] assures Us, that the Hydrophobia and Elephantiasis were both first taken Notice of in the time of Asclepiades the Physician; who liv’d in the Days of Pompey the Great, many Years later than either Hippocrates or Aristotle.