ii EXTEBNAL DIGESTIVE SECEETIONS 113 



food the absolute amount of juice secreted increases with the 

 amount ingested. For different kinds in equal quantities, the 

 absolute amount of secretion varies ; it is greater for meat than 

 for bread, for bread than for milk (Khizhin and Lobassoff, 1897). 



(A) The introduction of carbohydrates excites no secretion of 

 gastric juice (Barbera, 1898) ; that of fats may cause its diminution 

 or arrest if it is already present (Khizhin, 1895 ; Lobassoff, 1897). 



This inhibitory action of gastric secretion by fats has been 

 carefully studied by Pawlow's pupils. Their observations show 

 that not only is the total quantity of gastric juice diminished, but 

 the enzymic activity of the secretion is also depressed. Thus, 

 e.g. , on administering 400 grms. of flesh to a dog provided with 

 Pawlow's miniature stomach, about 40 c.c. of secretion was obtained 

 in the first four hours, with a peptic digestive power (measured by 

 Mett's method in mm.) equal to 5 '00. On adding 75 c.c. olive oil 

 to the 400 grins, flesh, a secretion of only 18 c.c. was obtained, 

 with a digestive power lower by 3 mm. 



The inhibitory action of fats is shown particularly in the first 

 period of digestion (in which the influence of psychical factors is 

 specially felt). Sham feeding in a dog operated on by Pawlow's 

 method, when the large stomach contains oil, or has been subjected 

 for some time to the action of oil, produces a secretion much less 

 in quantity and activity than the same sham feeding when the 

 stomach has not been acted on by fat. 



These observations have an important practical significance, 

 since they justify the long-established use of fats in therapeutics, 

 for the cure of gastric ulcers, or of gastric hyper-secretion which 

 predisposes to ulcers. 



(i) Alcohol in moderate doses excites, in excessive doses arrests 

 gastric secretion (Bernard, Lussana, Albertoni). Many observa- 

 tions have been macle upon the use of alcoholic beverages (wine, 

 beer, liqueurs) in relation to the gastric secretion. Many authors 

 admit that these excite gastric secretion. But it is still unknown 

 whether this is by simple psychical reflexes (sight, smell, agreeable 

 taste) or by direct excitation of the mucous membrane. 



Frouin and Pekelharing showed that on administering alcoholic 

 solutions per rectum the increase in secretion was to be attributed 

 to the absorption of alcohol in the blood, by which the cells of the 

 gastric glands are excited immediately, or mediately by the nerves, 

 to an extent corresponding with the amount of alcohol absorbed. 



(k) With an empty stomach there is normally no gastric 

 secretion, provided there are no central taste stimuli to provoke it 

 reflexly. On opening the tap of the cannula of a gastric fistula in 

 a dog that has fasted for over twenty-four hours, only mucus as a 

 rule flows out, which usually gives an acid, more rarely a neutral 

 or alkaline reaction. In a woman with oesophageal occlusion due 

 to cancer of the cardia, operated on by gastric fistula by Postempski, 



VOL. II I 



