126 PHYSIOLOGY CHAP. 



Delezenne). When acetic, hydrochloric, lactic, or weak carbonic 

 acid is injected, a certain amount of secretion is observed. The 

 secretion obtained with these acids is serous, fluid, colourless if 

 the solution is weak, lemon-yellow or pinkish if more concentrated. 

 It has a very slight lipolytic action. Acids combined with pepsin 

 or with the alimentary proteins also excite enteric secretion. The 

 higher fatty acids dissolved by bile, and soap solutions (which at 

 once set free the fatty acids when introduced into the loop of 

 Vella) are more powerful than any other substance in exciting 

 enteric secretion. 



Besides being more copious, the secretion excited by the 

 higher fatty acids (oleic acid) has quite different physical 

 characters ; it is dense, ropy, and contains a number of enzymes. 

 Bile and alkalies produce no noticeable secretion. 



Masloff obtained rich secretions from the intestinal fistula 

 (preternatural anus) in dogs, with subcutaneous injections of 

 pilocarpine. Vella confirmed the same on his isolated loop of 

 intestine. 



The physiological conditions for the secretion of succus 

 entericus during digestion are as follows. In the isolated loop, 

 where no food can penetrate, a secretion of juice (more or less 

 abundant according to the nature of the food) is seen some time 

 after the meal. This tends to increase for a certain time, and 

 only ceases at the seventh to eighth hour of digestion. The time 

 at which the secretion reaches its maximum varies greatly, and 

 seems to depend on the varying nature of the food. The total 

 quantity of secretion that can be collected after 8 to 10 hours 

 does not exceed 8 to 12 c.c. 



Data in regard to the chemical composition of the succus 

 entericus differ with the animal used and the method by which 

 it is collected. The fluid that issues from the isolated loop of the 

 lower tract of the small intestine (ileum), is, according to Thiry, 

 thin, opaline, yellowish, strongly alkaline, of specific gravity TO 10. 

 It contains 



Water 97-2-97-9 per cent. 



Solids 2-2- 2-8 



Protein 0'7- 0-12 



Ash 0-7- 0-8 



In addition to sodium chloride the ash contains large quantities 

 of sodium carbonate, as on adding acids t the succus entericus 

 effervesces. It always exhibits a few enzymes, to which its weak 

 digestive powers are due. Its action is diastatic on starch and 

 glycogen, invertive of saccharose into dextrose, curdling on milk, 

 emulsifying on fats, similar to that possessed by all alkaline 

 fluids. Succus entericus is further credited with the property of 

 splitting up fibrin, which cannot be very important, but Schiff, 



