BILE, PANCREATIC JUICE, AND SUCCUS ENTERICUS. 285 



ent on the alkali and the alkali-albumin present. The proteolytic ferment, 

 trypsin, as ordinarily prepared seems to be proteid in nature and capable of 

 giving rise by digestion to peptone ; but it may be doubted, as in the case 

 of pepsin and other ferments, whether the pure ferment has yet been isolated. 

 There are no means of distinguishing the amylolytic ferment of the pan- 

 creas from ptyalin. The term pancreatin has been variously applied to 

 many different preparations from the gland, and its use had, perhaps, better 

 be avoided. 



The action of pancreatic juice or of the infusion or extract of the gland, 

 on starch, is seen under all circumstances, whether the animal be fasting or 

 not. The same may probably be said of the action on fats. On proteids 

 the natural juice, when secreted in a normal state, is always active. The 

 glycerin extract or aqueous infusion of the gland, on the contrary, as we 

 have already explained ( 208), is active in proportion as the trypsinogen 

 has been converted into trypsin. 



SUCGUS Entericus. 



219. When in a living animal a portion of the small intestine is liga- 

 tured, so that the secretions coming down from above cannot enter its canal, 

 while yet the blood-supply is maintained as usual, a small amount of secre- 

 tion collects in its interior. This is spoken of as the succus entericus, and is 

 supposed to be furnished by the glands of Lieberkiihn, of which we shall 

 presently speak. 



Succus entericus may be obtained by the following method, known as that of 

 Thiry modified by Vella. The small intestine is divided in two places at some 

 distance (30 to 50 cm.) part. By fine sutures the lower end of the upper section 

 is carefully united with the upper end of the lower section, thus, as it were, cut- 

 ting out a whole piece of the small intestine from the alimentary tract. In suc- 

 cessful cases union between the cut surfaces takes place, and a shortened but other- 

 wise satisfactory canal is re-established. Of the isolated piece, the two ends are 

 separately brought through incisions in the abdominal wall, and their mouths care- 

 fully fastened in such a manner that each mouth of the piece opens on to the ex- 

 terior. During the process of healing two fistulae are thus established, one leading 

 to the beginning of and the other to the end of a short piece of intestine quite iso- 

 lated from the rest of the alimentary canal ; by means of these openings a small 

 quantity of fluid can be obtained. 



The quantity secreted is said to be considerably increased by the administration 

 of pilocarpine. 



Succus entericus obtained from the dog by the above method is a clear 

 yellowish fluid having a faintly alkaline reaction and containing a certain 

 quantity of mucus. It is said to convert starch into sugar and proteids into 

 peptone (the action being very similar to that of pancreatic juice), to split 

 up neutral fats, to emulsify fats, and to curdle milk. It is also said to con- 

 vert rapidly cane-sugar into grape-sugar, and by a fermentative action to 

 convert cane-sugar into lactic acid, and this again into butyric acid, with 

 the evolution of carbonic acid and free hydrogen. 



According to the above results succus entericus is to be regarded as an 

 important secretion acting on all kinds of food. But even at its best its 

 actions are slow and feeble. Moreover, many observers have obtained nega- 

 tive results, so that the various statements are conflicting. Besides, we have 

 no exact knowledge as to the amount to which such a secretion takes place 

 under normal circumstances in the living body. We may, therefore, con- 

 clude that, at present at all events, we have no satisfactory reasons for sup- 

 posing that the actual digestion of food in the intestine is, to any great 

 extent, aided by such a juice. 



