406 COEEELATION OF PHYSICAL AND VITAL FOKCES. 



the production of Motion, Heat, Light, and Electricity by 

 living bodies ; touching more slightly upon the phenomena of 

 Growth and Development, which constitute, in the eye of the 

 physiologist, the .distinct province of vitality. In a memoir 

 of my own, " On the Mutual Relations of the Vital and Phys- 

 ical Forces," published in the Philosophical Transactions for 

 1850,* I aimed to show that the general doctrine of the " Cor- 

 relation of the Physical Forces " propounded by Mr. Grove, 

 was equally applicable to those Vital forces which must be 

 assumed as the moving powers in the production of purely 

 physiological phenomena ; these forces being generated in 

 living bodies by the transformation of the Light, Heat, and 

 Chemical Action supplied by the world around, and being 

 given back to it again, either during their life, or after its 

 cessation, chiefly in Motion and Heat, but also to a less de- 

 gree in Light and Electricity. This memoir attracted but 

 little attention at the time, being regarded, I believe, as too 

 speculative ; but I have since had abundant evidence that the 

 minds of thoughtful Physiologists, as well as Physicists, are 

 moving in the same direction ; and as the progress of science 

 since the publication of my former memoir, would lead me 

 to present some parts of my scheme of doctrine in a different 

 form,f I venture to bring it again before the public in the 

 form of a sketch (I claim for it no other title), of the aspect 

 in which the application of the principle of the " Conserva- 

 tion of Force " to Physiology now presents itself to my mind. 



* At this date the labours of Dr. Mayer were not known either to my- 

 self or (so far as I am aware) to any one else in this country, save the late 

 Dr. Baly, who a few months after the publication of my Memoir, placed in 

 my hands the pamphlet, " Die Organische Bewegung ; " to which I took the 

 earliest opportunity in my power of drawing public attention in " The Brit- 

 ish and Foreign Medico-Chirurgical Review " for July, 1851, p. 237. 



f I have especially profited by a Memoir on the Correlation of Physical, 

 Chemical, and Vital Force, and the Conservation of Force in Vital Phenom- 

 ena, by Prof. Le Conte (of South Carolina College), in Silliman's American 

 Journal for Nov., 1859, reprinted in the Philosophical Magazine for 1860. 



