A single man cannot operate upon Nature without calling his own muscles into play under the control of his own brain.
 Karl Marx, Das Kapital (1867). copy citation

add
Author Karl Marx
Source Das Kapital
Topic muscles self-control
Date 1867
Language English
Reference
Note Translated by Samuel Moore and Edward Aveling
Weblink https://www.marxists.org/archive/marx/works/download/pdf/Capital-Volume-...

Context

“So far as the labour-process is purely individual, one and the same labourer unites in himself all the functions, that later on become separated. When an individual appropriates natural objects for his livelihood, no one controls him but himself. Afterwards he is controlled by others. A single man cannot operate upon Nature without calling his own muscles into play under the control of his own brain. As in the natural body head and hand wait upon each other, so the labour-process unites the labour of the hand with that of the head. Later on they part company and even become deadly foes. The product ceases to be the direct product of the individual, and becomes a social product, produced in common by a collective labourer, i.e., by a combination of workmen, each of whom takes only a part, greater or less, in the manipulation of the subject of their labour.” source