|Graeme Hunter's 2000 Vital Forces, on a history of the various "vital force" theories of nature. |
In 1774, German physician Friedrich Medicus (1736-1808) introduced the term “vital force” (lebenskraft) as the force responsible for processes such as digestion and respiration. In 1795, German physician Johann Riel (1759-1813), in his article “On the Vital Force”, posited five types of forces: physical force, vital force, vegetative force, animal force, and mental force.  German chemist Hermann Kolbe (1818-1884) commented in 1845: 
“If the concept, however, is extended to include the assumption that the vital force, pushes out and replaces the original forces of matter, so that the latter cease to operate, then one has gone too far; for at times it is possible by experimentation to unite the lifeless fundamental substances into compounds identical with those that are formed through vital processes.”
French chemist Marcellin Berthelot has been described as the official executioner of the vital force theory, a concept about which he had an expressly philosophical bias against: 
“It is the object of these researchers to do away with life as an explanation, wherever organic chemistry is concerned.”
His aim here, although this seems to have have a feel of the defunct theory of life in it, according to chemistry historian Forris Moore (1918), was to show that all the transformations of the organic world are due to the play of simple chemical and mechanical forces acting in a mechanical way.  In his 1860 "Organic Chemistry Founded on Synthesis", his so-called masterpiece, Berthelot described his breakthrough insight, in his introduction, of how he obtained a first organic compound (formic acid): 
"Solely by a combination of time and ordinary affinities."
This seems, in some way, to be a forerunner to the debate that will eventually surround the premise of the synthesis of a human molecule (person), a large animate 26-element organic compound (see: human free energy of formation).
In 1920, American mathematician William Sidis, one the last of the dying breed of scientists to attempt to find a physical basis for the vital force concept, in his The Animate and the Inanimate, outlined a rather convoluted second law based "split universe model", consisting of a forward universe and a reverse universe, to "supply the basis for the idea of vital force", as he put it. 
● Vital energy
1. (a) Hunter, Graeme K. (2000). Vital Forces: the Discovery of the Molecular Basis of Life (pgs. 55). Academic Press.
(b) Teich, Mikulas. (1970). “The Historical Foundations of Modern Biochemistry” (pg. 172), in: The Chemistry of Life: Eight Lectures on the History of Biochemistry (editor: Joseph Needham) (pgs. 171-91). CUP Archive.
2. (a) Scott, George P. (1985). Atoms of the Living Flame: an Odyssey into Ethics and the Physical Chemistry of Free Will (pg. 92). University Press of America.
(b) Adolphe Wilhelm Hermann Kolbe – Wikipedia.
3. Scott, George P. (1985). Atoms of the Living Flame: an Odyssey into Ethics and the Physical Chemistry of Free Will (pgs. 67, 92, 95). University Press of America.
4. Moore, Forris J. (1918). A History of Chemistry (pg. 204). McGraw-Hill.
5. Sidis, William J. (1920). The Animate and the Inanimate (§7: Theories of Life). Draft stage 1916; Published: R.G. Badger, 1925.
6. Hunter, Graeme K. (2000). Vital Forces: the Discovery of the Molecular Basis of Life (pgs. 55). Academic Press.