In 1806 American physician Shadrach Ricketson (1768-1839) published the book 'Means of Preserving Health and Preventing Diseases', in which he mentioned that he often saw patients whose tendency, situation or work did not allow them to exercise and therefore quickly became pale, weak and ill. He warned that laziness and luxury created more diseases than labor and industry.
In 1808, British scientists William Allen (1770-1854) and William Hasledine Pepys (1775-1856) described a device in which the subject had to breathe through a mouthpiece. Via hand-operated valves the test person inspired from a water-sealed gazometer and expired in a mercury-sealed gazometer. Only the carbon dioxide production and the ammonium density were measured. The research was successful and both published their findings in the work 'On the changes produced in atmospheric air and oxygen gas by respiration'.
The British anatomist John Barclay (1758-1826) published 'The muscular motions of the human body' in 1808, in which he analyzed the muscular functioning of each movement, as well as its applications in surgery.
German mechanic and inventor Karl Heinrich Klingert (1760-1828) became world famous with his invention of diving equipment. In 1810 he also developed a tool for healing gymnastics, with which one could simultaneously practice arms and legs.