THE GENERAL EFFECT OF STIMULATION 83 



alterations of the relations of the cell to its surrounding medium, 

 etc. Hence this mere increase of volume of the cell in growth 

 forms the source of an infinite mass of alterations in the activities 

 of cell metabolism, which we briefly term its "development," and 

 which by constant progression, leads either to a process of cell 

 division, and with this to a correction of existing disorder, or 

 finally to irreparable disturbances ending in death. In this way 

 an inseparable relation exists between increase of volume and 

 the development of living substance. We have seen, however, 

 that the catalytic reactions of stimulation, which at first only 

 produce an alteration of rapidity of the individual constituent 

 processes, if of prolonged duration or of frequent recurrence, 

 secondarily efifect a change of volume of the entire living organ- 

 ism. One can, therefore, hardly reject the conclusion that seeing 

 the close interworkings of the individual part process of metab- 

 olism, every change of rapidity of a single member, if of pro- 

 longed duration or of frequent occurrence, must finally lead to 

 qualitative alterations of the entire metabolism. In consequence 

 there results an important dependence between catalytic stimula- 

 tion and metamorphic reaction. Indeed, it is not unlikely that 

 the metamorphic reactions, which are especially seen in the con- 

 tinued effect of weak stimuli, result from alterations of rapidity, 

 which the individual members of the vital processes have 

 primarily undergone from this influence. 



It is perhaps expedient to cite a concrete instance in illustration. 

 A simple example is furnished by asphyxiation. If oxygen is 

 withdrawn from any living organism, the result is a depression 

 of its oxydation processes. Here there is primarily only a change 

 in rapidity, especially a retardation of oxydation processes. The 

 metabolism, however, proceeds, the disintegration of living sub- 

 stance continues, although at a slower rate, but produces an 

 accumulation of other products. Whereas formerly during the 

 existence of a sufficient supply of oxygen an oxydative disintegra- 

 tion of nitrogen-free groups into carbon dioxide and water took 

 place, both of which could easily be eliminated from the cell, the 

 anaerobic disintegration furnishes only complex products, having 

 a higher carbon content, such as lactic acid, fatty acids, aceton, 



