DIGESTION IN THE STOMACH. 63 



the stomach has been devised by Pawlow (see Fig. 6). By sim- 

 ultaneously collecting the secretions from the main stomach and 

 the miniature stomach after sham feeding, it was found that they 

 ran strictly parallel with one another, in amount as well as in 

 strength of secretion. The secretion in the miniature stomach 

 therefore accurately mirrors the secretion occurring in the main 

 stomach, and so permits us to study this when food is actually 

 being digested. . 



By introducing food directly into the main stomach through 

 a fistula, it was found, by observations on the secretions from the 

 miniature stomach, that very little secretion occurred until after 

 some time, provided of course that precautions had been taken, 

 as by experimenting on a sleeping animal, not to excite the appe- 

 tite juice. There was found to be great discrimination in the 

 nature of the adequate stimulus for this local secretion ; mechani- 

 cal stimulation of the gastric mucosa, contact with alkaline fluids, 

 such as saliva, or with white of egg, failed to produce any secre- 

 tion ; water had a slight effect, milk still more, whereas a marked 

 secretion occurred when a decoction of meat or meat extract, or 

 a solution containing the half digested products of peptic diges- 

 tion (such as Witte's peptone) was placed in the main stomach. 

 It was further observed, when meat was directly placed in the 

 stomach, that the juice which collected in the pouch increased, 

 both in quantity and in strength, after the first hour, and that 

 it continued to flow even after four hours, thus indicating that 

 the primary stimulus had come from the extractives in the meat, 

 but that, as the protein of the meat became digested, further 

 stimulation occurred on account of the proteose and peptones 

 liberated. 



This local stimulation is independent of the medullary nerve 

 center that controls secretion of the appetite juice, for it still oc- 

 curred after both vagi had been divided or even after destruc- 

 tion of the sympathetic nerve pelxuses in the abdomen. It might, 

 however, still be a nervous reflex involving the local nerve struc- 

 tures (plexus of Auerbach) in the walls of the stomach, although 

 this is not so probable as that it is dependent upon some chemical 

 excitation of the gland cells by substances appearing in the blood 



