And, to prevent mistakes, I must advertize you, that I now mean by elements, as those chymists that speak plainest do by their principles, certain primitive or simple, or perfectly unmingled bodies; which not being made of any other bodies, or of one another, are the ingredients of which all those called perfectly mixt bodies are immediately compounded, and into which they are ultimately resolved: now whether there be any such body to be constantly met with in all, and each, of those that are said to be elemented bodies, is the thing I now question.

The inspired and expired air may be sometimes very useful, by condensing and cooling the blood that passeth through the lungs; I hold that the depuration of the blood in that passage, is not only one of the ordinary, but one of the principal uses of respiration.

I am not ambitious to appear a man of letters: I could be content the world should think I had scarce looked upon any other book than that of nature.

In an arch each single stone which, if severed from the rest, would be perhaps defenceless is sufficiently secured by the solidity and entireness of the whole fabric, of which it is a part.

I think myself obliged, whatever my private apprehensions may be of the success, to do my duty, and leave events to their Disposer.

If the juices of the body were more chymically examined, especially by a naturalist, that knows the ways of making fixed bodies volatile, and volatile fixed, and knows the power of the open air in promoting the former of those operations; it is not improbable, that both many things relating to the nature of the humours, and to the ways of sweetening, actuating, and otherwise altering them, may be detected, and the importance of such discoveries may be discerned.

There is no less invention in aptly applying a thought found in a book, than in being the first author of the thought.