304 THEORETICAL BIOLOGY 



impossible for a melody to derive its law from the relationship 

 of the notes (even if the related notes should mutually attract 

 one another) as for the building-sequence of an organism 

 to be deduced from the chemical affinity of the germinal 

 elements (i.e. from their peg and socket joints, together with 

 the polar tension). 



What seems to us essential — namely, whether or not the 

 rhythm of an action is given all prepared by the framework 

 of the organs — is for Nature of only secondary importance. 

 The process of the building-sequence is not laid down in the 

 germ by a framework of any kind whatsoever ; for the actions 

 of the completed animal the same holds true — the rhythm of 

 the same action that in the one creature is fixed by the frame- 

 work, in another may dispense with this fixation. 



In the majority of animals the process of digestion is 

 conducted along fixed routes by a series of organs, which 

 are joined to one another. Students of the digestive process 

 strive, through exact knowledge of the alimentary canal, to 

 learn how to read off from it, as from a progressive musical 

 notation, the act of digestion, which begins at the mouth 

 and ends at the anus. This is rendered possible, because the 

 food- balls, as they move along, are aU the time being con- 

 ducted past fresh receptors and effectors (glands and muscles). 

 Each section of the gut receives in an altered condition the 

 food-balls pushed forward by effectors of the preceding 

 section, and possesses receptors constructed on a corre- 

 spondingly different plan, which are able, by means of their 

 effectors, to induce a further change ; and so it goes on. One 

 part links up with the other in unbroken series, and this chain 

 performs a chain of separate actions, which, taken collectively, 

 lead to the disintegration and absorption of the food. 



In this process an obvious rhythm is expressed, which 

 it is the task of the physiology of digestion to study in all 

 its details. Nierenstein found exactly tho same rhythm 



