Chapter XXXIX: Madam,

I will not dispute your _Authors_ opinion concerning the Plague of Men, which he says,[1] _doth not infect Beasts, neither doth the plague of Beasts infect Men_; but rather believe it to be so: for I have observed that Beasts infect onely each other, to wit, those of their own kind, as Men do infect other Men. For example: the Plague amongst Horses continues in their own kind, and so doth the Plague amongst Sheep; and for any thing we know, there may be a plague amongst Vegetables, as well as amongst Animals, and they may not onely infect each other but also those Animals that do feed on those infectious Vegetables: so that Infections may be caused several ways; either by inbreathing and attracting or sucking in the Poyson of the Plague, or by eating and converting it into the substance of the body; for some kinds of poyson are so powerful, as to work onely by way of inbreathing. Also some sorts of Air may be full of infection, and infect many Men, Beasts, Birds, Vegetables, and the like; for Infections are variously produced, Internally as well as Externally, amongst several particular Creatures; for as the Plague may be made internally, or within the body of a particular Creature, without any exterior infection entring from without into the body, so an external Infection again may enter many several ways into the body. And thus there be many contagious diseases caused meerly by the internal motions of the body, as by fright, terror, conceit, fancy, imagination, and the like, and many by the taking of poysonous matter from without into the body; but all are made by the natural motions or actions of animate matter, by which all is made that is in Nature, and nothing is new, as _Solomon_ says; but what is thought or seems to be new, is onely the variation of the Motions of this old Matter, which is Nature. And this is the reason that not every Age, Nation, or Creature, has always the like diseases; for as all the actions of Nature vary, so also do diseases. But to speak of the Plague, although I am of opinion, that the Plague of Beasts doth not infect Men, unless they be eaten; nor the plague of Men, Beasts; yet Magistrates do wisely in some places, that in the beginning of the plague of Men, they command Dogs and Cats to be kill'd, by reason, as your _Author_ saith, _The skins and flesh of Brutes may be defiled with our Plague, and they may be pestiferous contagions unto us._ I will add one thing more, which doth concern the Poyson of Measels, whereof your _Author_ is saying,[2] That _it is onely proper to humane kind._ What kind of Measles he means, I know not; but certainly Hogs are often affected with that disease, as is vulgarly known; but whether they be different diseases in their kinds, and proceed from different motions, I will let others inquire. And so I rest,

Madam,

_Your faithful Friend_

_and Servant._

[1] In the Plague-grave, _ch._ 17.

[2] _Ch._ Call'd, _The Lunar Tribute_.