The bad Effects of such Fumes as This will be the more certain, because the inspired Mineral Particles twitch and irritate the Membranes, which are hereupon contracted to that Degree, as not to be able to recover their Tone, and so the Force and Action of the Lungs is quite lost.
It appears from all This not to be at all necessary to make any farther Enquiry into the particular Nature of these Mineral Particles, since they do in this Case act chiefly by their Gravity, which is common to ’em all. Tho’ indeed the Greenish Colour of the Earth, together with its Subacid Taste, very much (as L. di Capoa observes) like to that of the Phlegm of Vitriol, seem to declare them, if not altogether, yet principally at least, to be Vitriolick.
To conclude this Part of our Discourse; I think it a sufficient Confirmation of this Reasoning, that in Frogs kill’d in this Grotta, the Bladders of the Lungs (more visible otherwise and distinct in these Creatures than in most others), were found subsided, and quite empty of Air [(161)]. But if any one desires a farther Proof, he may, according to these Principles, make (as Lionardo di Capoa [(162)] did) an Artificial Mephitis; for if Antimony, Bismuth, or any other such Mineral be finely powdered, and moistened with Aqua Fortis, or Spirit of Nitre, there will arise a great Heat, and a thick dark Smoak, in which, as in the Grotta de Cani, Torches are extinguish’d, and Animals, tho’ but slowly, stifled and kill’d. And this Effect will be more sensible, and equal to the most Violent Mephites, if the Antimony or Marcasite be mix’d with Bitumen, and the Spirit of Nitre, or Aqua Fortis, intirely depurated from all its Phlegm.
And thus I have shewn how Death may enter at the Nostrils, tho’ nothing properly Venomous be inspired. It were perhaps no difficult Matter to make it appear, how a lesser Degree of this Mischief may produce Effects, tho’ seemingly very different from these now mention’d, yet in reality of the same Pernicious Nature; I mean, how such an alteration of the common Air as renders it in a manner Mephitical, that is, increases its Gravity, and lessens its Elasticity, (which is done by too much Heat, and at the same time too great a Proportion of watery and other grosser Particles mixt with it) may be the Cause of Epidemic Diseases, and, it may be, more especially of those, which by Reason of their untoward Symptoms, are usually call’d Malignant.
For it is very Remarkable, that Hippocrates [(163)] observ’d the Constitution of the Air, which preceded Pestilential Fevers, to be great Heats, attended with much Rain and Southern Winds; and Galen [(164)] takes Notice, that no other than a moist and hot Temperament of the Air brings the Plague it self; and that the Duration of this Constitution is the Measure of the Violence of the Pestilence. Lucretius [(165)] is of the same Mind, for in his admirable Description of the Plague of Athens, These Diseases, says He, either come from the Air, or arise from the Earth,
——Ubi Putrorem humida nacta est
Intempestivis Pluviisq; & Solibus icta.
In short, the general Histories of Epidemic Distempers, do almost constantly Confirm thus much, and would have done it more, if the vain Notion of Occult Venoms had not prepossess’d the Minds of Authors, and made Them regardless of the manifest Causes.
And this is notorious enough in those Countries where Malignant Diseases are most rife; Thus it is a very common Observation in the East-Indies, that during the dry Heats the Season is Healthful, but when the Rains fall immediately upon the Hot Weather, then untoward Fevers begin to threaten.
The same is observ’d in Africa; for (as Joan, Leo [(166)] relates) if Showers fall there during the Sultry Heats of July and August, the Plague and Pestilential Fevers insue thereupon, with which whosoever is infected hardly escapes.
And here I might, by Reflecting on the Use and Necessity of Respiration, and the particular manner of performing It, (of which I have hinted something already) and considering withal the true Nature of Fevers, easily shew how such a Constitution of the Air, as this is, must necessarily produce such Effects; might run over the Propositions of Bellini; which as they do plainly evince Malignant and Pestilential Fevers to be owing to a viscid and tenacious Lentor or Slime, which at first obstructs the Capillary Arteries, and afterwards being dissolved by Heat, Ferments with the Blood, and changes it into a Mass unequally Fluid and Glutinous, and therefore unfit for all the Operations of the Animal OEconomy; so it would be no uneasie Task to prove, that Air at the same time Hot and Moist, being less able to comminute and break the Arterial Fluid in the Lungs than is necessary, in order to prepare it for Secretions, it is no wonder, if when the Blood passing thro’ the Capillary Vessels arrives at the Secretory Organs, the Cohæsion of its Parts not being sufficiently removed, instead of deriving several Juices out of it into the Glands, it leaves its most Glutinous and Viscid Parts sticking about the Orifices of these Vessels; which tho’ they may at first be wash’d away by the repeated Impulses of the succeeding Blood, yet the Cause continuing, and these Strokes growing still Weaker and Weaker, (from a lesser quantity of Spirits being separated, and hence a more languid Contraction of the Heart) These Obstructions are increas’d to that Degree as not to be remov’d, till by the Violent Agitation of a greater Heat, this Slimy Mucus is thrown into the Blood again, and there in the Nature of a Ferment so disturbs its Mixture, and changes its Compages, as to make it a Fluid of quite different Properties, that is, altogether unfit for the same Functions or Offices.