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ACTION OF THE PANCREATIC JUICE. 



In pancreatic digestion a body resembling alkali-albumin, which passes into a 

 globulin-like body, and ultimately into a peptone, is formed. Of the peptones so 

 produced, one is called anti-peptone, and it is not further changed, but part of the 

 proteid is changed into hemi-peptone. This body, when acted upon, yields leucin 

 and tyrosin. When putrefaction takes place, the bodies above-mentioned are also 

 formed. We might represent the action of trypsin thus : Proteid + trypsin + 1 

 per cent, sodium carbonate, kept at 38 C. = formation of a globulin-like body, and 

 then anti-peptone and hemi-peptone are formed. 



Anti-peptone 



undergoes no 

 further change. 



It seems that trypsin in pure water can act slowly upon fibrin to produce 

 peptone. Pepsin cannot do this without the aid of an acid.] 



[Kiihne's Pancreas Powder. This is prepared by the prolonged extraction of 

 fresh pancreas of ox with alcohol and then with ether. If the dry powder be 

 extracted for several hours with a 1 per cent, solution of salicylic acid, and filtered, 

 a fluid with powerful proteolytic, but no diastatic, properties is obtained. Several 

 hours afterwards much tyrosin may separate out, which, of course, must be removed 

 by nitration. The clear fluids when mixed with fibrin and a 1 per cent, solution of 

 sodic carbonate, rapidly digests fibrin. If it be desired to obtain a true pancreatic 

 digestion, with none of the products of putrefaction, the mixture must be strongly 

 " thymolised " with a 25 per cent, alcoholic solution of thymol (Kuhne).] 



[Setschenow finds that egg-albumin, boiled in a vacuum at 35-40 C. , is more rapidly digested 

 than fibrin by a specially prepared trypsin.] When proteids are boiled for a long time with 

 dilute H 2 S0 4 , we obtain peptone, then leucin and tyrosin ; gelatin yields glycin. Hypoxanthin 

 and xanthin are obtained in the same way by similarly boiling fibrin, and the former may even 

 be obtained by boiling fibrin with water (Chittenden). 



It is very remarkable that the juice of the green fruit of the papaya tree, or Carica papaya, 

 possesses digestive properties {Roy, Wittmack), and that the action is due to peptonising ferment, 

 closely related to trypsin, and called caricin or papain. [It forms a true peptone, an inter- 

 mediate body, and leucin and tyrosin. It also contains a milk-coagulating ferment (Martin).'] 

 The milky juice of the fig-tree has a similar action. Sprouting malt, vetch, hop, hemp during 

 sprouting, and the receptacle of the artichoke contain a peptonising ferment. Leucin, tyrosin, 

 glutamic and aspartic acids, and xanthin are formed in the seeds of some plants ; hence we 

 may assume that the processes of decomposition in some seeds are closely allied to the fermenta- 

 tive actions that occur in the intestine. 



III. The action on neutral fats is twofold : (1) It acts upon fats so as to 

 form a fine permanent emulsion. (2) It causes neutral fats to take up a 

 molecule of water and split into glycerine and their corresponding fatty acids : 

 (C 57 H 110 O 6 )+ 3(H 2 0) = (C,H 8 3 )+ 3(C 18 H 3fl 2 ). 



Tristearin. Water. Glycerine. Stearic Acid. 



The latter result is due to the action of an easily -decomposable fat-splitting 

 ferment {CI. Bernard), also called steapsin. Lecithin is decomposed by it into 

 glycero-phosporic acid, neurin and fatty acids. The fatty acids thus liberated are 

 partly saponified by the alkali of the pancreatic and intestinal juices, and partly 

 emulsionised by the alkaline intestinal juice. Both the soaps and emulsions are 

 capable of being absorbed ( 191). 



EmuMfication. The most important change effected on fats in the small intestine is the 

 production of an emulsion, or their subdivision into exceedingly minute particles ( 191). This 

 is necessary in order that the fats may be taken up by the lacteals. If the fat to be emulsified 

 contain a free fatty acid, i.e., if it be slightly rancid, and if the fluid with which it is mixed 



