464 riGESTIOX. 



duodenum, jejunum, and ileum as well as from the liver and pancreas 

 by hydrochloric acid. 



We know very little, positively, in regard to the gastric secretion in 

 man. According to the earlier authorities the irritants may be mechan- 

 ical, thermic, and chemical. Among the chemical excitants we include 

 alcohol and ether, which in too great a concentration bring about no 

 physiological secretion, but rather the transudation of a neutral or 

 faintly alkaline fluid. Certain acids, such as carbonic acid, neutral 

 salts, meat extracts, spices, and other bodies also belong to this group. 

 The reports on this subject are unfortunately very uncertain and con- 

 tradictory. 



The question as to how far the observations made by PAWLOwand 

 his school can be applied to man is of special interest. Many observa- 

 tions on this question have been collected 1 and they compare favor- 

 ably with the observations made upon dogs. Thus in man a psychic 

 secretion of gastric juice can be brought about, and it has also been 

 observed that it can be stopped by emotions. As in clogs, so also in man, 

 after sham feeding, a secretion takes place after a pause, the duration 

 of which varies in different cases. In some cases, as in dogs after meat 

 feeding, the pause was about five minutes. The chewing of indifferent 

 bodies did not affect the glands, while bodies acting upon the organs of 

 smell and taste had an exciting action. UMBER observed besides this, that 

 after the introduction of a nutritive enema into the rectum, a secretion 

 of gastric juice was produced by reflex action. 



From these observations of HORNBORG and UMBER, as well as from 

 some earlier observations of SCHULE, TROLLER, RIEGEL, and ScHEUER, 2 

 we conclude that in man the psychic secretion is much less than that 

 produced by the introduction of food or bodies having a pleasant taste. 

 That the preparation of the food in the mouth has an essential influence 

 upon the secretion is proved without doubt, but we do not agree as to 

 how this action takes place. Certain experimenters consider the secreted 

 and swallowed saliva as the most essential factor in this action, while 

 others believe that the act of chewing, and still others that the chemical 

 action and the sense of taste, are the most important. 



In regard to the action of saliva, HEMMETER finds that after the 

 extirpation of the salivary glands, the introduction into the stomach 

 of chewed food soaked with dog-saliva, has no special action upon the 



1 Hornborg, Maly's Jahresb., 33, 547; Umber, Berl. klin. Wochenschr., 1905; 

 Cade and Latarjet, Compt. rend. soc. biol., 57; Kaznelson, Pfliiger's Arch., 118; 

 Bogen, ibid., 117; Bickel, Deutsch. med. Wochenschr., 32, and Maly's Jahresb., 36, 

 411. See also Maly's Jahresb. 39, 40, and Bioch, Centralbl. 12. 



2 The literature may be found in Umber's work, 1. c. 



