has already been impressed, in some degree, on your mind also, by the contents of my former letters on the subject; and it is with a view to impress it more deeply that I now take up my pen, for the purpose of presenting to your consideration those two grand organs of the bodily frame, called the heart and the lungs, and especially the effects of their combined agency.
On this occasion, however, I shall not waste your time with repeating what you must already know, viz. that the heart is a hollow fleshy cavity in the human breast, the use of which is, by its regular pulses, to propel the blood into the arteries, and receive it back from the veins, and thus to promote its circulation through every part of the body; and that the lungs are respiratory organs, formed for the purpose of maintaining a perpetual communication with the atmospheric air, and by alternate distension and contraction, or what is termed inspiration and expiration, of admitting into the body what is salubrious from the air, and at the same time of casting off from the body what, if remaining in it, might prove noxious.
It would be an equal waste of your time, to detain you by a minute description of the form or construction of these organs, because from every writer on the anatomy of the human body, your pious mind will be
