DIGESTION. 



267 



trypsin into leucin and tyrosin, but is not so changed by pepsin; the 

 antipeptone cannot be further split up. The products of pancreatic 

 digestion are sometimes further complicated by the appearance of certain 

 faecal substances, of which iiidol and naphthilamine are the most impor- 

 tant. (Kiilme.) 



When the digestion goes on for a long time the indol is formed in con- 

 siderable quantities, and emits a most disagreeable faecal odor, which was 

 attributed to putrefaction till Kiihne showed its true nature. All the al- 

 buminous or proteid substances which have not been converted into pep- 

 tone, and absorbed in the stomach, and the partially changed substances, 

 i.r.. the parapeptones, are converted into peptone by the pancreatic juice, 

 and then in part into leucin and tyrosin. 



(2.) Nitrogenous bodies other than proteids, are not to any extent 

 altered. Mucin can, however, be dissolved, but not gelatin or horny tis- 

 sues. 



(3.) Starch is converted into glucose in an exactly similar manner to 

 that which happens with the saliva. As mentioned before, it seems not 

 unlikely that glucose is not formed at once from starch, but that certain 

 dextrines are intermediate products. If the sugar which is at first formed, 

 as is stated by some chemists, be not glucose but maltose, at any rate the 

 pancreatic juice after a time completes the whole change of starch into 

 glucose. There is a distinct amylolytic ferment (Amylopsin) in the pan- 

 creatic juice which cannot be distinguished from ptyalin. 



(4.) Oils and fats are both emulsified and split up into their fatty 

 acids and glycerin by pancreatic secretion. Even if part of this action is 

 due to the alkalinity of the medium, it is probable that there is a third 

 distinct ferment (Steapsin) which facilitates the change. 



Several cases have been recorded in which the pancreatic duct being 

 obstructed, so that its secretion could not be discharged, fatty or oily 

 matter was abundantly discharged from the intestines. In nearly all 

 these cases, indeed, the liver was coincidently diseased, and the change 

 or absence of the bile might appear to contribute to the result; yet the 

 frequency of extensive disease of the liver, unaccompanied by fatty dis- 

 charges from the intestines, favors the view that, in these cases, it is to 

 the absence of the pancreatic fluid from the intestines that the excretion 

 or non-absorption of fatty matter should be ascribed. 



(5.) It possesses the property of curdling milk, containing a special 

 (rennet) ferment for that purpose. The ferment is distinct from trypsin, 

 and will act in the presence of an acid (W. Roberts). 



Conditions favorable to the Action of the Pancreatic Juice. 

 These are similar to those which are favorable to the action of the saliva, 

 and the reverse (p. 231). 



