(1182)
in the Spring⟨.⟩ We must therefore inquire into other more true causes of old Age and Death, which to me seem to be the following;
I suppose, that the Blood is the principle of life, as far as 'tis vital, that is, in motion by the hot particles contained therein; so that those, who expire by Age, do not dye for being destitute of blood, which is found abundant and laudable enough in their vessels, and which hath been sufficiently repaired till then; but because it ceaseth to be vital, by reason of the too easie dissipation of the igneous particles, which make it such: Which, in my opinion, comes to pass, as it doth in Wine, which evaporates and loseth its strength by the fault of the Vessel, which by some opening or other gives passage to what gives vertue to the Wine. The Tunicles and Membranes of the Veins and Arteries which inclose the blood, wearin time away and wax-thin, and their Texture gives, and breaks in several places, at which apertures the igneous particles abandon the blood: As in Stuffs and Cloth (whose woof is in a manner like that of the Tunicles) the Threds by wearing do loosen, and break, insomuch that many holes are made in it as in a Sieve. So that, if we had the Art to reinforce and to strengthen anew those Coats and Membranes, that they might not let slip what maketh the blood vital, the life would be preserved perpetually. For a proof of which, this may serve for the present, that the life of many dying persons is maintain'd, for some time, by making them swallow some hot and spirituous liquor, as spirit of Wine, or some Essence, by which the blood is fortified and quickned for some moments: But as this reinforcement of life, conveyed to the heart, and running into the Veins, soon slips out, so also this new vigor passeth away quickly.
As there is no reason to despair of finding out such Medicins, or Aliments, as are proper to strengthen the Coats and Membranes of the Vessels, so as they may at all times retain the fiery and spirituous corpuscles of the blood, as well as in the time of Youth; We may also hope to be enabled to maintain the blood in a condition alwayes to furnish alike, as in our vigorous Age, for all the functions of life: The Engine of our body being not unlike to a Chymists Furnace, which at first well retaining theheat,
