CHEMISTRY. 



97 



examined l>y Prof. Franklaml, of the Royal 

 Institution. IK' starts out with the axiom that 

 an animal, no matter however high its organi- 

 /.itiuii may In-, can no more generate an amount 

 <>f force ca|ial>le of moving a grain of sand than 

 a stone can fall upward or a locomotive drive a 

 train without fuel. All that an animal can do 

 is, to lil'crate that store of force or potential 

 energy which is locked up in its food. It is 

 the chemical change which food suffers in the 

 1'ody of an animal that liberates the previously 

 pent-up forces of that food which now make- 

 t heir appearance in the form of actual energy, as 

 heat and mechanical motion. The tw.o chief 

 forms of force thus manifested are heat and 

 muscular motion or mechanical work, and these 

 have been almost universally traced to two dis- 

 tinct sources the heat to the oxidation of the 

 food, and the mechanical work to the oxidation 

 of the muscle. This was the doctrine first pro- 

 mulgated by Baron Liebig, in his " Chemico- 

 Physiological Essays." Prof. Frankland's ex- 

 periments lead him to somewhat different con- 

 clusions, as follows : 



1. The muscle is a machine for the conversion 

 of potential energy into mechanical force. 



2. The mechanical force of the muscles is de- 

 rived chiefly, if not entirely, from the oxidation 

 of matters contained in the blood, and not from 

 the oxidation of the muscles themselves. 



3. In man, the chief materials used for the 

 production of muscular power are non-nitro- 

 genous; but nitrogenous matters can also be 

 employed for the same purpose, and hence the 

 greatly increased evolution of nitrogen under 



the influence of a flesh diet, even with no 

 greater muscular exertion. 



4. Like every other part of the body, the 

 muscles are constantly being renewed: but 

 this renewal is not perceptibly more rapid dur- 

 ing great muscular activity than during com- 

 parative quiescence. 



6. After the supply of sufficient albnmenized 

 matters in the food of man, to provide for the 

 necessary renewal of the tissues, the best ma- 

 terials for the production both of internal and 

 external work are non-nitrogenous matters, such 

 as oil, fat, sugar, starch, gum, etc. 



6. The non-nitrogenous matters of food, which 

 find their way into the blood, yield up all their 

 potential energy as actual energy; the nitro- 

 genous matters, on the other hand,Jeave the 

 body with a portion (one-seventh) or their po- 

 tential energy unexpended. 



7. The transformation of potential energy 

 into muscular power is necessarily accomplished 

 by the production of heat in the body, even 

 when the muscular power is exerted externally. 

 This is doubtless the chief and probably the 

 only source of animal heat. 



The limits of this article will not permit the 

 reproduction of all the statistics and tables by 

 which Prof. Frankland justifies his conclusions. 



The following statement of the energy devel- 

 oped by various articles under combustion in 

 oxygen, is specially interesting. The values, 

 however, experimentally obtained for these 

 articles, must be understood as the maxima, 

 and hold good only on condition that the food 

 is digested and passes into the blood. 



The Sulphides. M. J. Pelouze, at the session 



of the French Academy, in January, presented 



a Memoir of th* Sulphides. He prepared pure 



monosulphide of sodium by passing sulphuretted 



VOL. vi. 7 A 



hydrogen into soap-makers' lye. The crystals 

 were recrystallized once or twice until they 

 were colorless and quite pure. With a solution 

 of this salt, a weak solution of acetate and chlo- 



