The Publication in Question, titled An Extract of a Letter Written by Monsieur de Martel of Montauban to the Publisher, Concerning a Way for the Prolongation of Humane Life, together with Some Observations Made in the Southern Parts of France, English'd as Follows, contains the author's reflections on the Causes of the Debilitation of Nature's strength in the course of man's life, and how these Causes might be Ameliorated, leading, naturally, to a means of achieving Eternal Youth through Medical Science.
The author agrees with the illustrious Messrs. Bacon and Sanctorius that the extinction of the natural heat and dessication of the Radical humour, as previously understood by Philosophers, seem not sufficient explanation for the causes of Age. However, Monsieur de Martel disagrees with Sanctorius's assertion that "the Fibres do dry up, that they can no more be renew'd," noting that even old Oxen have at certain times more or less marrow (though not, he is quick to point out, owing to the cycles of the moon).
Blood, claims Monsieur de Martel, is the Principle of Life, but notes that a Man typically has no Shortage of Blood when he dies. What causes this man to age, then, is that the Veins and Arteries which inclose the Blood, much like the Chymists Furnace, develop apertures, which, being insufficiently repair'd, do ease the dissipation of the igneous particles, such that they abandon the Blood. He reasons, then
As in Stuffs and Cloth (whose woof is in 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. . . . There is no reason to despair of finding out such Medicins, or Ailments, as are proper to strengthen the Coats and Membranes of the Vessels, so that they may at all times retain the fiery and spirituous corpuscules of the blood, as well as in the time of Youth.The author also reports on the method of making Muscadin Wine in Frontignac.
For those wishing further to pursue Monsieur de Martel's ideas on the Acquisition of Eternal Youth through preservation of the blood's vital igneous particles, or those wishing to instruct their Slaves on how best to produce a nice Muscadin, the citation information is:
de Martel, M. (1670). An Extract of a Letter Written by Monsieur de Martel of Montauban to the Publisher, Concerning a Way for the Prolongation of Humane Life, together with Some Observations Made in the Southern Parts of France, English'd as Follows Philosophical Transactions of the Royal Society of London, 5 (57-68), 1179-1184 DOI: 10.1098/rstl.1670.0020