Now as we every Day observe, that what is thrown out from Liquors in a Ferment, is capable of inducing the like Motion in another Liquor of the same kind, when duly mixed with it; so we may very well suppose in the present Case, that the _Saliva_, which is it self one of the most Fermentative Juices in Nature, being turgid with Fiery, Saline Particles thrown into it out of the boiling Blood, when it comes by means of a Wound to be Incorporated with the Arterial Fluid of any One, does by Degrees raise a preternatural Effervescence in it; the Effects of which will necessarily be most felt in those Parts which being tender, are the least able to refill the distension of the Blood Vessels; such are the Stomach, and especially the Brain; and hereupon _Deliria_, with _Maniacal_, and such like Symptoms, will easily insue. A Person thus affected may be said in a Degree to have put on the _Canine_ Nature, tho’ his Reason be all this time untouch’d and intire, may Bite, Howl, _&c._ because the _like_ violent Agitation of the Blood in Him as was in the Dog will present like _Species_, and consequently (so far as their different Natures will allow) produce like Actions; just as it has been observed, that _Sheep_ bitten by a Mad Dog, have run at the Shepherd like so many Dogs to Bite him; so much can an Alteration of the Blood and Spirits do. And as a Timorous Creature may be imboldened, so we oftentimes see Persons Courageous enough by a change made in the Blood by Evacuations, that is, by want of Force and Motion in that Fluid, made sheepish Cowards, in despight of their Reason, so long as that Defect is continued. But the main difficulties in this matter are, the Mischief discovering it self so long after the Bite, and the _Hydrophobia_. 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.