THE PROCESS OF EXCITATION 99 



temperatures, and still less to apply it to those instances in which 

 the production of energy following stimulation is suddenly in- 

 creased to great amounts. Let us suppose that the disintegration 

 process occurs in two phases, the first of which after the type of 

 the fermentation of dextrose separates the molecule into larger 

 fragments, while in the second phase these fragments are split 

 up through oxydation into the formation of carbon dioxide and 

 water. We can then say with certainty that in the first stage only 

 a comparatively small amount of energy production occurs, for 

 energy production by enzymic processes of this kind is never 

 great; the second phase, on the other hand, must be associated 

 with a very considerable energy production, for by the addition 

 of oxygen and the formation of carbon dioxide and water the 

 strongest affinities possible are combined. With this assumption 

 in certain cases, as, for instance, in the sudden production of 

 energy in muscle contraction, which necessarily occurs in the 

 purely oxydative phase of the whole process, the view is forced 

 upon us, that, in these cases, the entrance of oxygen into the 

 molecule from the very beginning, even the first impact, produces 

 oxydative decomposition of the whole molecule. The view that, 

 in the reactions of warm-blooded animals, which occur with great 

 rapidity and considerable energy production, the oxygen pri- 

 marily explosively breaks up the whole carbon chain, certainly 

 presents no more difficulties than the supposition that the sim- 

 pler substances are attacked secondarily, provided sufficient oxy- 

 gen be present. This method would be obviously the simplest. 

 This is, however, mere speculation and a definite decision between 

 the two possibilities cannot be made at present. However, 

 whether the process takes place in two phases, an anoxydative 

 and an oxydative, or simply in an oxydative phase, in any case, 

 the sudden discharge of energy in the aerobic organism set free 

 by the stimulus, is brought about by the addition of oxygen. 



This is a highly important fact and as such requires the most 

 thorough confirmation, and is best accomplished by the investi- 

 gation of the state of excitation of aerobic substances on the 

 withdrawal of oxygen. Experience gained by observation in this 

 respect on a great number of living substances shows that exci- 



