DIGESTION 269 



wonder that a mechanism so constituted should easily 

 become deranged. One is impressed, too, by the increas- 

 ing importance attached by physiologists to the part 

 played by the nervous system in the inception and co- 

 ordination of the various muscular and chemical func- 

 tions of the organs concerned, which amply justifies the 

 view long held by physicians, that functional disorders of 

 digestion are really manifestations of an affection of the 

 nervous centres. 



Experiment has made clear to us how it is that dis- 

 order of one section of the alimentary apparatus may 

 throw out of gear the working of other sections, and how 

 healthy intestinal digestion is dependent upon a normal 

 state of the stomach, and that in its turn upon the 

 efficient carrying out of the preliminary processes of 

 digestion in the mouth ; and it follows from this that, in 

 trying to cure disturbances in one part of the alimentary 

 canal, we must often direct our treatment to the part 

 which lies above it. The cure of gastritis by attention 

 to the teeth, and of some forms of chronic diarrhoea by 

 the administration of hydrochloric acid, are instances in 

 point. At the same time, one cannot help being im- 

 pressed, from the physiological point of view, by the 

 liberal provision made in the digestive tract for the 

 supplementing of defective action of one part by a more 

 vigorous exercise of function by others, and the lesson of 

 this to the physician is one of hope and encouragement. 



