SOME NEW VIEW POINTS IN NUTRITION 401 



In the animal body, however, there is no such accumulation of de- 

 composition products as is implied here, but the principle involved 

 may possibly admit of application. 



It is generally understood that muscular energy comes primarily 

 from the decomposition or oxidation of non-nitrogenous material, either 

 of the food or of the tissues ; and in man we are accustomed to measure 

 the amount of muscular work performed by the amount of oxygen con- 

 sumed and the amount of carbon dioxide thrown out. In other words, 

 the potential energy of the foodstuffs is made available through oxida- 

 tion. This, however, is not always the case. Thus, in Ascaris, a round 

 worm inhabiting the intestine of some of the higher animals, we have 

 an animal that can live and show extremely active movements for days 

 at a time without any appreciable amount of oxygen. Carbon dioxide 

 is given off abundantly, however, thereby implying a cleavage or process 

 of disintegration in which energy is freely liberated for the necessi- 

 ties of the animal's machinery. It is quite apparent, however, that 

 oxidation is not the source of muscular energy in these organisms. It 

 may be claimed, and perhaps justly, that such an illustration as this 

 can not be applied legitimately to animals higher in the scale of life, 

 yet there is experimental evidence from various sources pointing in the 

 same direction. Thus, Stoklasa 10 has shown that organs from the 

 higher animals, notably the lungs, liver, pancreas and muscle, yield on 

 pressure fluids, from which by precipitation with alcohol and ether 

 enzymes can be separated, having the power of producing in perfectly 

 sterile solutions of sugar — and with exclusion of micro-organisms — 

 alcoholic fermentation. The proportion of carbon dioxide and alcohol 

 formed under these conditions is the same as produced by yeast. 

 Eemembering that in alcoholic fermentation sugar is simply split 

 apart into alcohol and carbon dioxide, it is readily seen that the 

 liberation of a certain amount of energy is possible by simple cleavage 

 of the sugar molecule and without the intervention of oxygen. This 

 then is a form of anaerobic metabolism or respiration, possibly an- 

 alogous to that which occurs in Ascaris, where carbohydrates are 

 broken down and energy set free for the needs of the organism. Again, 

 Hermann years ago proved that a freshly excised muscle, from which 

 all free oxygen had been separated by exposure to a vacuum, when 

 placed in an oxygen-free medium could be made to work and give off 

 carbon dioxide. Other data of a similar nature might be presented 

 showing quite conclusively the power of animal tissues to carry on 

 various decompositions of complex organic matter with an output of 

 carbon dioxide and with consequent liberation of energy where free 

 oxygen is entirely wanting. These are facts, however, well known to 

 physiologists, but they serve to emphasize the validity of the present 



10 Zentralblatt fiir Physiologie, Band 17, p. 465. 

 vox,, lxxii. — 26. 



