362 



Dr, TT, Marcet on the Nutrition of 



added to the fluid during the evaporation, so that there was no 

 difficulty in taking up the residue for the combustion with 

 soda-lime; 15"7 parts of nitrogen corresponded to 100 of albu- 

 men. Notwithstanding the variety of substances into which 

 albumen is thus transformed,, we find a relation between the 

 albuminous materials of both classes which does not vary 

 between wide limits. Thus : — 



Mean... 



Albumen 

 coagnlable 

 and colloid, 

 2nd class. 



Material from 



albumen 



crystalloid, 



3rd class. 



Relation. 



6-62 

 5-67 



5-428 



3-64 

 3-622 

 3-622 

 3-913 



1-82 : 1 

 1-57 : I 

 1-45 :1 

 1-30 : 1 



5-746 



3-699 



1-56:1 



1 



Hence the nutritive fluid of flesh contains a mean of rather 

 over one half more albumen than is present in the solution of 

 the effete material. Now it is obvious that if a muscle should 

 retain a certain composition, which it does within certain limits, 

 it must draw upon the blood in proportion to its waste. There- 

 fore for every 3*699 grammes of albumen (in the crystalloid 

 form) on its way out, 200 grammes of flesh must draw 3'699 

 grammes of albumen colloid and coagulable from the blood. But 

 we find 200 grammes of muscular tissue to contain a mean of 

 0-746 grammes of colloid coagulable albumen ; and as the 

 albumen must regulate the supply of the other substances 

 muscular tissue requires for its nutrition, it follows that about 

 one third of the whole of the nutritive material present in flesh 

 is in store, not being required for immediate use. Therefore 

 if the blood, from want of food, were incapable of nourishing 

 flesh, yet the muscle would apparently continue for a certain 

 time derinng food from the material accumulated within the 

 tissue. This appears to be a provision of nature to allow of 

 muscular exercise during prolonged fasting. Of course this view 

 must be considered a mere deduction open to future investi- 

 gation. 



The relation of phosphoric acid and potash to albumen in 

 the third class varies in the different analyses, the former be- 

 tween 13'31 and 17*12 per cent, (of the albumen), and the 

 latter between 19*80 and 22*17 per cent.; but it is highly in- 

 teresting to observe that these two substances, relatively to each 

 other, are present in muscle as effete material precisely in the 

 proportion of 43 of phosphoric acid to 57 of potash, correspond- 



