436 Disturbances of Digestion. 



mining a hypergemia, the latter an ansemia of the organ affected. 

 Centres for the vascular nerves are located in the floor of the fourth 

 ventricle, in the dorsal and lumbar cord and in the ganglionic and 

 nervous plexuses which regulate the tone or ordinary state of con- 

 traction of the arteries and the dilatation or constriction of the ves- 

 sels to any calibre, and which are located about the walls of the ves- 

 sels themselves. Stimulation of the fibres regarded as vasoconstric- 

 tor causes diminution of calibre, auc-emia and lowered temperature 

 of the organ involved ; afterwards passing into paralysis, from 

 which dilatation results. Paralysis of the vascular nervous centres 

 also induces dilatation of the vessels and rapid lowering of blood 

 pressure (section of cord, paralyzing poisons). Stimulation of the 

 vasodilators causes marked dilatation of arteries, capillaries and 

 veins and is induced especially by local toxic influences. 



Disturbances of Digestion. 



Diseases of the mouth, tongue, jaws and teeth all interfere with 

 the taking of food and with mastication as well as the insalivation 

 of the food within the mouth. The supply of nutritive material is 

 thus diminished according to the grade and duration of such faults, 

 and conditions of failure of nutrition and starvation are brought 

 about. As the secretion of the gastric glands is in reflex associated 

 relation with the movements of chewing so as to insure the imme- 

 diate bathing of the swallowed bolus in proper juices (Pawlow), it 

 is to be expected that in case of insufficient mastication the food 

 taken into the stomach will be provided with a deficient amount of 

 gastric juice and will therefore of necessity remain a longer time 

 in the stomach. 



The movements of mastication mechanically cleanse the mouth of 

 its mucus and bacteria (immediately after prolonged chewing of 

 food the mouth is almost aseptic) ; anything which causes diminu- 

 tion of these movements favors marked accumulation of micro- 

 organisms, as a result of which acid fermentations take place in the 

 mouth, facilitating decay of the teeth, accumulation of tartar on the 

 teeth, pharyngeal catarrh, etc. 



In various diseases of the mouth (as foot and mouth disease), 

 in a number of toxic disturbances (mercurialism) and nervous affec- 

 tions (trigeminus), there ensues from direct or indirect nervous 

 irritation an increased flow of saliva, the secretion dribbling from 

 the mouth (salivation, ptyalisui). Dribbling of saliva may also be a 

 symptom of paralysis of the lips. 



