396 E. Frankland on the Source of Muscular Power. 
lungs by the blood, and is absolutely necessary for muscular 
activity. 
For two decades this doctrine sank into oblivion; and it is 
only within the last two years that it has been again advanced, 
chiefly by Haidenhain,* Traube, and, to a limited extent, by 
Donders.’ 
Experimental evidence was, however, still wanting to give 
missing link in the following words: “The question now arises 
what quantity of heat is generated when muscle is burnt to the 
products in which its constituent elements leave the human 
body through the lungs and kidneys? At present, unfortu- 
nately, there are not the experimental data required to give an 
accurate answer to this important question, for neither the heat 
of combustion of muscle nor of the nitrogenous residue (urea) 
e is known.” Owing to the want of these data, the 
numerical results of the experiments of Fick and Wislicenus 
are rendered less conclusive against the hypothesis of muscle 
combustion than they otherwise would have heeti while similar 
determinations, which have been made by Edward Smith, 
Haughton, Playfair, and others, are even liable to a total misin- 
terpretation from the same cause. 
_ The speaker stated that he had supplied this want by the ca- 
lorimetrical determination of the actual energy evolved by the 
combustion of muscle and of urea in oxygen. Availing him- 
self of these data he then proceeded to the consideration of the 
problem to be solved, the present condition of which might be 
thus summed up:—It is agreed on all hands that muscular 
Mechanische Leistung Wirmeentwickelung und Stoffumeatz bei der Muskel- 
~ press, the speaker has become aware that ‘ 
Lawes and Gilbert advocated this doctrine in 1852, and repeatedly since; their 
opinions being founded upon ppm on the feeding of cattle. 
us oo influss des Kochsalzes, des Kaffeés und der Muskel- 
ing Stoffwechsel,’ p. 150. Munich, 1860. 
* Phil. 1861, p. 747. > M 
Stace Oe eee SO See ae ee See Ree 
; 
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