In human chemistry, Yves Guyot (1843-1928) was a French economist noted for his 1903 to 1918 human molecular theory descriptions.
In 1903, Guyot used the term molécules humaines (the English translation being ‘human molecules’), referring to a person as a molecule. The quote is: 
“If only wheat and cattle, its industry cannot rely on its domestic market, if it is active, one cannot believe that the future belongs to stagnant civilizations. It belongs to civilization in which the fluid human molecules roll ever on each other.”
Likewise, in his 1918 book The Guarantees of Peace, he states: 
“It is the rapid evolution of human groups: the large current conflict is between those who seek to freeze the situation and those who adapt to fluid civilizations, whose molecules are in constant movement.”
1. Guyot, Yves. (1903). “La These de M. Balfour” (“The Thesis of Stuart Balfour”), The Monthly Review (molécules humaines, pg. 11). 13: 9-16.
2. Guyot, Yves. (1918). Les garanties de la paix: ptie Lesleçons du passé (The Guarantees of Peace: the Lessons of the Past) (molécules, pg. 165). F. Alcan.
● Yves Guyot – Wikipedia.