RETAIN THE NITROGEN. 



and over again. A bee will move with extreme activity upon 

 a diet of pure honey or sugar, and thus by a more complex organi- 

 zation convert the chemical force of carbo-hydrates, by union 

 with oxygen, into motion, which the yeast cell could not do, 

 while its tissues do not waste, though supplied with so little 

 albumen, thus showing the existence of compensatory processes. 

 In spite of the supply of oxygen to the extreme points by exten- 

 sion of the trachese beyond the blood-vessels in insects, no mere 

 oxidation can be the cause of evolution of muscle-force, for the 

 theory that an animal could convert the heat of carbo-hydrates 

 into motion, though still taught in some text-books, was long 

 since disproved by Clausius and Voit, followed by Tick. As to 

 where this storing up of oxygen takes place, no doubt it maybe 

 partly in the blood, which must be richer in circulating albumi- 

 nous matter, and no doubt also part of this store is consumed in 

 oxidating and removing effete products, but the chief part must 

 be in the muscles themselves, for a muscle when detached from 

 the body, with all the blood washed out, and when placed in 

 a vacuum or in indifferent gases, will still contract and do work 

 for a time. And in the living body, J. Kanke states, " I could 

 prove that the capacity for doing work of the muscle rises and 

 falls with the amount of solids contained in it, so that a muscle 

 is the more capable of work the richer it has been in normal 

 muscle-stuffs during the state of rest " (635). Likewise, it is. 

 known that the amount of carbonic acid in the venous blood 

 of the active muscle is greater than can be accounted for by the 

 disappearance of oxygen.* 



During work from stimulation by voluntary or reflex motor 

 nerves, both the formation of this consumable matter by oxida- 

 tive synthesis from the blood and its dissolved oxygen, and the 

 consumption of it are immediately increased. But this in- 

 crease does not equal the loss, and consequently the store 

 wastes, while the neutralization and removal of the acid pro- 

 ducts does not' keep pace with their formation, and therefore 

 the fatigue-stuffs accumulate hence fatigue, and recovery after 



*, The venous blood of the active muscle contains 3 vol. per cent. less, 

 oxygen and 4.1 per cent, more carbonic acid than that of the resting 

 muscle. Sczelko \v. 



