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. This Effect will be the more certain, because a damp Air upon the surface of the Body checks insensible Perspiration, so that a great quantity of this being detained, the Obstructions are still greater in the small Tubes; whereas indeed upon the Account of a more than ordinary Heat, this Discharge ought now to be in an increased Proportion. Such a Disposition of the Blood as this the Ancients call’d _Putrid_; and to speak plainly, it is a Beginning Stagnation, with a Succeeding Heat and Fermentation.