94 IRRITABILITY 



explosive combinations. Iodide of nitrogen, for instance, in a 

 manner similar to the living substance in the state of the metab- 

 olism of rest, constantly disintegrates even without the influence 

 of an impact. The disintegration is suddenly enormously in- 

 creased by the result of a jar. An explosion follows. In a like 

 manner the functional metabolism of rest is explosively exci- 

 tated by the stimulus, the transformation of the energy involved 

 likewise bears a similar relation. 



In both instances the transformation of energy, constant in the 

 resting state, is by the impact of the stimulus suddenly increased. 

 The dynamic method of investigation of the excitation process 

 with its physical indicators, forms, therefore, in many respects 

 an excellent addition to the chemical analysis. A development, 

 that is, exothermic formation, of energy can only occur in a 

 chemical process when the chemical affinities which are to be 

 combined are stronger than those which have been separated. 

 When this process is brought about by a simple impact, the energy 

 value of which bears no relation to that of the quantity of energy 

 in the process itself and which occurs with explosive rapidity, 

 then it can be simply a question of a liberation process, that is, 

 a process by which the impact brought about a conversion of 

 latent chemical energy into that of kinetic energy. The compari- 

 son of the functional excitation process with that of an explosion 

 does not, therefore, consist in a merely superficial analogy, but is 

 founded on the same dynamic principles. 



When we study the chemical process which occurs in the explo- 

 sive transformation of potential into kinetic energy we find two 

 types of chemical processes. The first type includes the synthetic 

 processes. For this, the synthesis of water from explosive gas 

 may serve as a simple example. Here the weaker affinities in 

 comparatively simple molecules (H -f- H and O + O) are sepa- 

 rated and stronger affinities are combined in the formation of 

 more complicated molecules (H + O + H). The second type 

 represents the process of cleavage. As example for the latter, the 

 explosive disintegration of nitroglycerine may be quoted. Here 

 the atoms, held together in a complex molecule by weaker affini- 

 ties, are changed by transposition of nitroglycerine. For in- 



