342 DIGESTION. 



verted into lactic acid before it is finally disposed of in 

 respiration. 



The rapidity with which the sugar-forming process at 

 the liver goes on seems to be influenced by various cir- 

 cumstances ; but, on the whole, Bernard's experiments 

 appear to prove that it is directly proportioned to the 

 rapidity of the portal circulation. Whatever expedites 

 this, increases the quantity formed, and vice versa. Hence 

 it is, probably, that irritation of various parts of the 

 nervous system, especially of the sympathetic, causes an 

 increased formation of sugar, by stimulating the portal 

 circulation. 



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 food 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 

 w-h'ich 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 



