114 



PHYSIOLOGY 



CHAP. 



Bocci constantly observed an acid reaction from the gastric niucosa, 

 twelve hours after the last meal. We must not assume from this 

 that gastric secretion is continuous. When gastric juice, with 

 all its chemical and physiological characters, flows from gastric 

 fistulae in animals or man, with a perfectly empty stomach, under 

 perfect physiological conditions, it can easily be shown that this 

 apparently spontaneous secretion is aroused by psychical taste- 

 suggestions (Pawlow). 



In order to study the course of gastric secretion, i.e. its quantitative and 

 qualitative modifications during digestion, it is convenient to employ 



FIG. 38. A, stomach of dog previous to Pawlow's operation, showing direction of principal 

 nerves. B, stomach after the operation, which has divided it into two, the large (K), and the 

 miniature stomach or blind sac (S), which is sutured to the abdominal walls (AA), and com- 

 municates with the exterior by means of a fistula. S, serous coat; muse., muscular coat; 

 muc., mucous membrane of wall of stomach operated on. 



Pawlow's " miniature stomach " or pouch, which served for most of the 

 experiments we have been discussing. It is prepared as follows : 



The first incision A, B (Fig. 38, A), which begins in the fundus of the 

 stomach, 2 cm. from its junction with the pyloric portion, is carried in the 

 longitudinal direction through all the coats of the anterior and the posterior 

 wall for 10-12 cm. along the great curvature. A triangular flap C, C is thus 

 formed. A second incision is made exactly at the base of this flap, but only 

 through the mucous membrane. The serous and muscular coats are left intact, 

 and pass from the main stomach into the flap, while the mucosa is completely 

 separated from it. The edges of the mucous membrane of both stomach and 

 flap are detached from the submucous tissue for l-l cm. from the wall of 

 the stomach, and 2-2 cm. from the wall of the flap. The posterior and 

 anterior margins of the mucous membrane of the stomach are then brought 

 together and sutured in a straight line from cardia to pylorus. The flap 

 is converted into a cup. Lastly, the margins of the incision, in the walls of 

 stomach and flap are stitched together. The cavity of the stomach is thus 

 restored, and the flap remains as a pouch, or small appendicular stomach 



