CHAP. II.] THE SECRETION OF GASTRIC JUICE. 77 



secretion of a very small quantity of gastric juice, a conclusion which 

 agrees with the observations of Heidenhain. 



Whenever a foreign body, such as the bulb of a 

 ca/ irrigation thermometer, is brought in contact with the interior of 

 but stm bet- the stomach, the mucous membrane is seen to become 

 ter, the pre- turgid, and a flow of gastric juice is set up. The sur- 

 sence of food, f ace O f the stomach is seen to be covered by " innumer- 



. a able lucid specks," which seem to burst and "discharge a 

 flow of gastric ,. . , A , . r ~ . \ . , , -. P /T> e 



j uice limpid, thin fluid over the whole gastric suriace (Beau- 



mont). Whilst mechanical irritation will invariably 

 occasion a flow of gastric juice, the best observers (Tiedemann and 

 Gmelin, Heidenhain, &c.), confirm the statement of Beaumont, that 

 by this means only a limited quantity of gastric juice can be obtained; 

 the effect, as Beaumont surmised, appears in this case to be a purely 

 local one. 



When instead of a foreign body, solid aliment enters the stomach, 

 the turgescence of blood-vessels of the organ is general and great, and 

 gastric juice is poured out in quantity and continuously. The cause of 

 the difference in the effect of purely mechanical stimulation and of 

 stimulation by food is yet doubtful. Some light seems thrown upon 

 it by an interesting observation of Heidenhain. This observer, as 

 will be explained at length in the sequel, has succeeded in separating 

 a portion of the cardiac end of the stomach from the rest of the organ, 

 retaining, however, its vascular and nervous connections. By sutures, 

 this portion of stomach is converted into a tube, blind at its inner end, 

 but possessing an opening, which is stitched to an incision in the 

 abdominal wall. Thus a tube with walls composed of cardiac end of 

 stomach can be obtained. Heidenhain observed that in a dog in 

 which such a procedure has been successfully carried out, secretion of 

 fluid from this stomach-tube came on from 15 30 minutes after food 

 had been taken into the stomach, and continued to the end of diges- 

 tion. If, however, a meal of indigestible substances were partaken of,' 

 secretion was much longer delayed, and would only occur when the 

 animal began to drink, lasting even then but a comparatively short 

 time. This observation, taken in connection with the fact that during 

 digestion of digestible food gastric juice is abundantly and continu- 

 ously secreted, whilst it is not so after mechanical irritation, points to 

 the fact that the products of digestion when absorbed act as the essen- 

 tial stimuli to the secreting structures of the stomach (Heidenhain), 

 and thus lead to the difference in behaviour of the stomach according 

 as it is thrown into action by mechanical stimuli or by digestible 

 food. 



It was observed by Bidder and Schmidt that in 

 may" be W SUP- ^ s w ^ g as tric fistulas in which salivary fistulse 

 posed to indi- na cl been established, and which had been starved, the 

 cate tiiat the sight of food caused an abnormal flow of gastric juice 1 . 



1 ' Sehr bemerkenswerth 1st, dass bei niichternen Thieren auch der blosse Anblick 



