Nature, as will taint the Blood of other Animals with those pestilential Requisites.
‘AS this kind of Contagion then can easily proceed from an infected Person at a great Distance, as often as the noxious Particles can reach another Person, and give that Degree of Coagulation and Fusion, as is necessary to a Pestilence; the more aggravated then will be this Calamity, and more easily spread, when a healthful Person is near to one already infected; and yet much more worse, if it is in Contact with those Parts, which more plentifully, and with a greater Impetus, breath out infected Steams, as if the Air arising from the Mouth and Lungs, which must be extreamly hot, or the Perspiration of a Carbuncle when it is greatly inflamed; for in this Case the exhaling Particles will be in their greatest Activity when nearest the recipient Body, and likewise more dense, that is, more numerous, and consequently of greatest Efficacy.
‘BUT it is not every one that is seized with a Pestilence from Contagion, by Means of Steams exhaling from any particular Parts of the Body; but only when these Steams, and the Air it self, hath joined
with, and interspersed through it Particles of vitiated Faculties; and then this Kind of Fever will easily be communicated, and necessarily ensue, not only on Account of what gets into the Body with the inspired Air, but because also the whole Body is surrounded with such an Infection, wherein the noxious Particles floating about on all Sides, will endeavour to penetrate through the Pores upon the Surface, and get that Way into the Blood; for although the Skin is thicker upon the Surface of the Body, than that Pellicle covering the Vessels in the Lungs, and for that Reason it requires longer Time for such Particles to get that Way into the Blood, and the Habit of the Body, yet it is no Argument that they cannot get that Way at all, and be admitted into the Juices.’
BY this we are able to gather, that when a Fever from some Faults in the Non-naturals comes to the highest Degree of Malignity, it makes such a Change in the animal Fluids as renders some Parts of them poisonous, and capable of exciting the like fermentative Motions, wheresoever they come into a proper Subject, without any of those procatarctic Causes as gave Rise to the Fever of the first Person seized.
OF what Nature then this Poison is we may conjecture from the Circumstances of its Production. All animal Bodies do more or less generate a Salt; or rather, in Proportion to the Strength of their digestive Powers, do they more or less subtilize the saline Particles which are taken in with their necessary Nourishment. This is abundantly manifest in the Distillation of many animal Substances, which plentifully yield a volatile Salt. But indeed in the Composition of this, in a natural and healthful State, there is joined a very subtilized Sulphur or Oil; which contempers and softens it into a Fitness for the Purposes of the OEconomy: And under this Modification, it becomes the Principle of Vitality, and the chief Instrument of animal Action; not unlike what this is conceived to be, is the common Sal volatile oleosum, or any other Spirits drawn from odorous Bodies.
IT matters not what Names Persons please to distinguish this by, in an humane Body; but that somewhat of this Kind is naturally the Produce of its digestive Powers, in the highest Degree of Comminution or Subtilization they are capable of bringing
any Thing to, no one will question; and that those minute Threads or Fibres, of which the whole is a Composition, are animated by it; or, to speak more strictly, owe to it their Elasticity and motive Faculties.
IT is hoped, that no one who hath been accustomed to Reasonings of this Nature, will find any Difficulty in conceiving such a Difference of Principles, so finely blended together, as here suggested of a saline, and an oleous, or humid Substance: And whosoever reads Bellini, or any others who have wrote in the same Manner, will find continual Regard had to those two Principles, even in the animal Spirits; for without it there can be no Notion had of what is so frequently mentioned, and which by their Effects we find must be true of them, that they are too dry, hot, active, fiery, and the like; or too humid, vapid, sluggish, viscid, &c. And it is further equally manifest, that in Proportion to the greater or lesser Degrees of Motion in those Fluids, from whence this subtile Composition is generated, and the Concussions of those fine Threads into which it is separated, will it err in one or other of the foregoing Extremes.
IN a Fever therefore, where the animal Fluids are in the highest Degree of Agitation, and from Causes too of a coagulating Nature, it ought to be no Wonder that even this subtile Union should be in some Measure dissolved, and the softer and more humid Parts broke and exhaled, so much as to leave the more rigid and saline ones not only unfit to lubricate those Elastick Threads, wherein they reside, but sharp and pointed enough to stimulate, contract, and harden them into all Loss of Motion.