THE ACTIVE FORCES OF LIVING ORGANISMS 83 



nervous system is both acted on by and reacts upon 

 the electro-chemical processes of metabolism. 



At the same time, it must be constantly borne in Relative 

 mind that the two forms of force, the electro-chemical dence of 

 and the nervous, though convertible, are in a certain chemical 

 measure independent of one another. This fact has neryons" 

 been strikingly illustrated in certain cases by the meta^ '" 

 section of almost all the nerves of the stomach,* which ''°^='"- 

 led, contrary to expectation, to no arrest of the 

 digestive processes, although it is well known that 

 with the nerves intact under conditions of emotional 

 stress or impaired health the chemical action of the 

 stomach is frequently very much disturbed. If we 

 keep these conditions of independence well in view we 

 shall see that we are not justified in concluding that, 

 because digestion will go on after section of most of 

 the nerves, there are none possessing a secretory 

 function analogous to that of the chorda-tympani. 

 Why, then, it will naturally be remarked, does section 

 of the latter nerve cause a cessation of the functional 

 activity of the gland ? But if we look deeper into the 

 matter we shall notice that the conditions in the 

 stomach and submaxillary gland, though analogous in 

 many respects, are not so in others. In the former Difference 

 case, the materials to be digested are directly in contact secretory 

 with the secreting glands ; in the latter case, there is a ^he'aub™ 

 long duct intervening. Therefore there is greater ^^^']^^^ 

 need of nervous action or nervous collaboration in the gj^^j^^gj, 

 submaxillary gland than in the stomach. 

 * Foster, loo. eit., p. 403. 



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