Of all the wild chimeras which have in all ages haunted the minds of fantastic dreamers none has taken so great a hold on its votaries, as the search for the Elixir Vitae or means of prolonging human life beyond its allotted span.
So starts the introduction to the Hermippus Redivivus. An 1885 book written by the obscure German intellectual, John Henry Cohausen. Only 350 copies where privately printed in Edinburgh, one of which got sent to Harvard University and is now digitized and available to the world through Google books.
The work is edited by Edmund Goldsmith of who the above quote is attributed, and was penned with good reason given the obscure nature of the work.
Cohausen himself is drawing deep on obscure work to create his work. Digging all the way back to Roman times in which remains an inscription that tells of a man, L. Clodius Hermippus, who lived to the age of 115 years by breathing in the breath of young women. In this case, young can be taken to mean children, and whether or not it was purely women is contested...in case anyone decides to try this at home.
According to a review of the work written by Sabine Baring-Gould in his book Curiosities of Olden Times Cohausen covers in great detail of how much salubrious "young" air would be needed to prolong life, and how the myth might have been manufactured from the viewing of mouth to mouth resuscitation of an old woman by a young lady.
It should be noted that as the story goes with the Roman, Clodius Hermippus, he probably had no such intimate relations, but more just surrounded himself with children so as to breathe in their air.
Cohausen takes things a step further, suggesting the need for direct mouth to mouth resuscitation, and even suggesting the possibility of distilling a young woman's breath into a potent elixir of youth.
As charming and pleasingly logical the notion is, the idea today, alas, is considered as nothing more than hot air.