CHEMICAL EXCITANTS OF GASTRIC SECRETION 10; 



Tliis brilliant confirmation of our third theory did away with the 

 necessity of specially testing the second. But although the same 

 results were repeatedly observed from the above experiment, and hence 

 in themselves constitute a valuable enrichment of our knowledge in this 

 field, the mechanism of their production required still further investi- 

 gation. The combination of starch with the proteids of flesh, might 

 produce its effects in various ways. It is conceivable that the paste 

 may strongly stimulate the trophic nervous mechanism without affect- 

 ing the true secretory. But another explanation is also possible. We 

 know already, from the second lecture, that after a meal of flesh the 

 juice from the second hour onwards continuously declines in digestive 

 power till near the end of secretion, when it again becomes more effec- 

 tive ; and since the psychic juice, which is present during the earlier 

 hours after the taking of food, always possesses a fairly strong digestive 

 power, the decline after the second hour must be ascribed to the 

 less potent influence of the chemical excitant of the flesh. If this be 

 so, it is possible that the starch paste may in some way restrain or 

 prevent the depressing action of the meat constituents. The material in 

 possession of the laboratory does not yet, however, enable us to settle 

 this question positively ; but nevertheless it argues considerable pro- 

 gress that we are able to raise it and take it experimentally in hand. 



Whatever the answer may be, we have here before us a new fact, 

 namely, that a material which of itself is unable to excite a gastric 

 secretion can alter the work of the glands in a decided and special 

 manner when combined with the active constituents of flesh. 



With the question just discussed, as to how starch is able to 

 influence the secretion of gastric juice, another one, namely, the 

 similar effect of fat, stands in natural connection. As in the case of 

 starch, fat also when tested by itself has no influence on the gastric 

 glands, but it does not necessarily follow that it would remain ineffec- 

 tive if introduced as the forerunner of, or in conjunction with, other 

 food materials. In the further investigation of the fat influence, a new 

 fact came to light which is important towards a knowledge of secretory 

 processes, just as the study of the mixture of starch and flesh revealed 

 an interesting point in the effect produced by the former upon the pro- 

 perties of the juice. 



One hundred cubic centimetres of Provence oil, which, as you already 

 know, produces no secretion, were poured into the main stomach of a dog 

 by means of the sound. Half an hour to an hour later, the dog was 

 given its usual ration of 400 grms. of flesh, but a totally different curve 

 of gastric secretion was observed to that obtained if the same food, 

 without oil, had previously been given (Dr. Chigiti). Instead of the 

 usual five to ten minutes, we had to wait half an hour to an hour before 



