IN _Æthiopia_ those prodigious Swarms of _Locusts_, which at some times cause a Famine, by devouring the Fruits of the Earth, unless they happen to be carried by the Winds clear off into the Sea, are observed to entail a new Mischief upon the Country, when they die and rot, by raising a _Pestilence_[43]; the Putrefaction being hightened by the excessive _Intemperance of the Climate_, which is so very great in this Country, that it is infested with violent _Rains_ at one Season of the Year, for three or four Months together[44]. And it is particularly observed of this Country, that the _Plague_ usually invades it, whenever Rains fall during the sultry Heats of _July_ and _August_[45], that is, as _Lucretius_ expresses it, when the Earth is _Intempestivis pluviisque et solibus icta_[46]. NOW if we compare this last Remark of the _Intemperance of the Climate_ in _Æthiopia_, with what the _Arabian_ Physicians[47], who lived near these Countries, declare, that _Pestilences_ are brought by _unseasonable_ Moistures, Heats, and want of Winds; I believe we shall be fully instructed in the usual Cause of this Disease. Which from all these Observations compared together, I conclude to arise from the _Putrefaction_ so constantly generated in these Countries, when _that_ is hightened and increased by the ill State of Air now described; and especially from the _Putrefaction_ of animal Substances. IT is very plain, that animal Bodies are capable of being altered into a Matter fit to breed this Disease: because this is the Case of every one who is sick of it, the Humours in him being corrupted into a Substance which will _infect_ others. And it is not improbable, that the volatile Parts with which Animals abound, may in some ill States of Air in the sultry Heats of _Africa_ be converted by Putrefaction into a Substance of the same kind: since in these colder Regions, we sometimes find them to contract a greater Degree of Acrimony than most other Substances will do by _putrefying_, and also more dangerous for Men to come within the reach of their Action; as in those pernicious, and even poysonous Juices, which are sometimes generated in corrupted Carcasses: Of which I have formerly given one very remarkable Instance[48], and, if it were necessary, many more might be produced, especially in _hydropic Bodies_, and in _cancerous Tumors_. Nay more, we find _animal Putrefaction_ sometimes to produce in these _Northern_ Climates very fatal Distempers, though they do not arise to the Malignity of the true _Plague_: For such _Fevers_ are often bred, where a large Number of People are closely confined together; as in _Goals_, _Sieges_, and _Camps_.