874 INFLUENCE OF THE NERVOUS SYSTEM. 



periraeut. There is much reason to believe that the secretion of Gastric 

 fluid is affected, in the same manner as that of the saliva, by the impres- 

 sions made by food upon the senses ; for it has been ascertained by Bidder 

 and Schmidt 1 that it is copiously effused into the stomachs of dogs that 

 have been kept fasting, when flesh or any other attractive food is placed 

 before them. That the secretion, on the other hand, is entirely suspended 

 by powerful mental emotion, seems almost certain, from the well-known in- 

 fluence which this has in dissipating the appetite for food, and in suspend- 

 ing the digestive process when in active operation. As a cheerful state 

 of feeling, on the other hand, seems to be decidedly favorable to the per- 

 formance of the digestive function, it probably exerts a beneficial influence, 

 as to both quantity and quality, on the secretion of gastric fluid. Of the 

 influence of mental states on other secretions concerned in the reduction 

 and appropriation of the food (such as the Biliary, Pancreatic, and intes- 

 tinal fluids), neither observation nor experiment has as yet afforded auy 

 satisfactory information. It is a prevalent, and perhaps not an ill-founded 

 opinion, that melancholy and jealousy have a tendency to increase the 

 quantity, and to vitiate the quality, of the Biliary fluid. Perhaps the dis- 

 order of the organic functions is more commonly the source of the former 

 emotion than its consequence ; but it is certain that the indulgence of these 

 feelings produces a decidedly morbific effect by disordering the digestive pro- 

 cesses, and thus reacts upon the nervous system by impairing its healthy 

 nutrition. A copious secretion of fetid gas not uufrequeutly takes place in 

 the intestinal canal, under the influence of any disturbing emotion ; or the 

 usual fluid secretions from its walls are similarly disordered. The tendency 

 to Defecation which is commonly excited under such circumstances, is not, 

 therefore, due simply to the relaxation of the sphincter aui (as commonly 

 supposed) ; but is partly dependent on the unusually stimulating character 

 of the faeces themselves. The same may be said of the tendency to Mictu- 

 rition, which is experienced under similar conditions ; the change in the 

 character of the urine becoming perceptible enough among many animals, 

 in which it acquires a powerfully-disagreeable odor under the influence of 

 fear, and thus answers the purpose which is effected in others by a peculiar 

 secretion. The halitus from the Lungs is sometimes almost instantaneously 

 affected by bad news, so as to produce fetid breath. The odoriferous secre- 

 tion of the Skin, which is much more powerful in some individuals than 

 others, is increased under the influence of certain mental emotions (as fear 

 or bashfuluess), and commonly also by sexual desire. The Sexual secretions 

 themselves are strongly influenced by the condition of the mind. When it 

 is frequently and strongly directed towards objects of passion, these secre- 

 tions are increased in amount, to a degree which may cause them to be a 

 very injurious drain on the powers of the system. On the other hand, the 

 active employment of the mental and bodily powers on other objects, has a 

 tendency to render less active, or even to check altogether, the processes by 

 which they are elaborated. 2 



1 Op. cit., p. 35. 



This is a simple Physiological fact, but of high Moral application. The Author 

 would say to those of his younger readers, who urge the wants of Nature as an ex- 

 cuse for the illicit gratification of the sexual passion, "Try the <-H'eetsof close nn /*- 

 tal application to some of those ennobling pursuits to which your profession introduces 

 you, in combination with vigorous bodily exercise (for the effects of which see 555), 

 before you assert that the appetite is unrestrainable, and act upon that assertion." 

 Nothing tends so much to increase the desire, as the continual direction of the mind 

 towards the objects of its gratification, especially under the favoring influence of 

 sedentary habits; whilst nothing so cHVctiially represses it, as the determinate exer- 

 cise of the mental faculties upon other objects, and the expenditure of nervous energy 



