DIGESTION IX SMALL INTESTINE. 337 



The channel by which, the influence of the nervous 

 system is conducted in the preceding and similar experiments 

 is not accurately known ; no theory having been perma- 

 nently established, which explains all the facts hitherto 

 observed in connection with the influence of the nervous 

 system on the production of glucose. 



Summary of the Changes which take place in the Food during 

 its Passage through the Small Intestine. 



In order to understand the changes in the food which 

 occur during its passage through the small intestine, it 

 will be well to refer briefly to the state in which it leaves 

 the stomach through the pylorus. It has been said 

 before, that the chief office of the stomach is not only to 

 mix into an uniform mass all the varieties of food that 

 reach it through the oesophagus, but especially to dissolve 

 the nitrogenous portion by means of the gastric juice. 

 The fatty matters, during their sojourn in the stomach, 

 become more thoroughly mingled with the other consti- 

 tuents of the f jod taken, but are not yet in a state fit for 

 absorption. The conversion of starch into sugar, which 

 began in the mouth, has been interfered with, although 

 not stopped altogether. The soluble matters both those 

 which were so from the first, as sugar and saline matter, 

 and those which have been made so by the action of the 

 saliva and gastric juice have begun to disappear by ab- 

 sorption into the blood-vessels, and the same thing has 

 befallen such fluids as may have been swallowed, wine, 

 water, etc. 



The thin pultaceous chyme, therefore, which, during the 

 whole period of gastric digestion, is being constantly 

 squeezed or strained through the pyloric orifice into the 

 duodenum, consists of albuminous matter, broken down, 

 dissolving and half dissolved, fatty matter, broken down, 

 but not dissolved at all, starch very slowly in process of 



