136 THE WORK OF THE DIGESTIVE GLANDS. 



assigned its proper place, and if clinical medicine maintains her worthy 

 desire of following out the experimental investigation of her problems, 

 she must in actual practice accord to appetite its old claim for con- 

 sideration and treatment. 



But notwithstanding the indifference of physicians to appetite in 

 itself, many therapeutic measures are based on the promotion of it. 

 And in this, the truth of empiricism makes itself irresistibly felt. 

 When the patient is enjoined to eat sparingly, or when he is restrained 

 from eating at all till the physician expressly permits, or again, when 

 he is (for instance, during convalescence) removed from his ordinary 

 surroundings and sent to an establishment where the whole life, and 

 particularly the eating, is regulated according to physiological needs 

 in all these cases the physician seeks to awaken appetite, and relies 

 upon it as a factor in the cure. In the first case, where the food is 

 prescribed in small portions, in addition to preventing the overfilling 

 of a weak stomach, the oft-recurrence of appetite juice, which is so rich 

 in quantity and so strong in digestive power, i?s of great importance. I 

 ask you here to call to mind one of our experiments in which food was 

 given in small portions to a dog, and thus led to a secretion of much 

 stronger juice than if the whole ration had been eaten at once. This 

 was an exact experimental reproduction of the customary treatment of 

 a weak stomach. And such a regulation of diet is all the more neces- 

 sary, since, in the commonest disorders of the stomach, only the surface 

 layers of the mucous membrane are affected. It may, consequently, 

 happen that the sensory surface of the stomach, which should take up 

 the stimulus of the chemical excitant, is not able to fulfil its duty, and 

 the period of chemical secretion, which ordinarily lasts for a long time, 

 is for the most part disturbed, or even wholly absent. A strong 

 psychic excitation, a keen feeling of appetite, may evoke the secretory 

 impulse in the central nervous system and send it unhindered to the 

 glands which lie in the deeper, as yet unaffected layers of the mucous 

 membrane. 



An instance of this, taken from the pathological material of the 

 laboratory, I have already related at the beginning of this lecture. It 

 is obvious in these cases that the indication is to promote digestion by 

 exciting a flow of appetite juice, and not to rely upon that excited by 

 chemical stimuli. From this point of view the meaning of removing a 

 patient, the subject of chronic weakness of the stomach, from his 

 customaiy surroundings, is also plain. Take, for instance, a mentally 

 ovei'strained individual, or a responsible official : how of ten does it happen 

 that he cannot for a moment distract his thoughts from his daily work. 

 He eats without noticing it, or eats and carries on his work at the same 

 time. This often happens, particularly in the case of people who live 



