Il6 OUR BODIES AND HOW WE LIVE 



164. The Pancreatic Juice and what it does. The pan- 

 creatic juice is secreted by a long, narrow, flattened gland called 

 the pancreas, or sweetbread. It lies behind the stomach and 

 is often said to resemble a dog's tongue (Fig. 73). 



The pancreatic juice, by means of 

 its three ferments, finishes the work 

 which the saliva began. It acts 

 chiefly upon the starchy foods which 

 have escaped the action of the saliva, 



"" ^ * e 



*** - and changes them into sugar. It also 



'.-' * ; 



'"' J'*-' follows up the work of the gastric 

 : *.";* ***. juice, and acts upon the proteids 



FIG. 75. Vertical Section which have not been digested in the 

 of intestinal Vim ; Cross- stomach, changing them into peptones. 

 Section below, with The pancre atic juice acts upon the 



Black Dots representing c 



Glandular Openings. ' dr P s of fat m such a wav as to s P ]lt 



them into glycerin and a fatty acid. 



The latter now unites with the alkali of the pancreatic juice 

 and the bile, and forms soap. It also makes what is called 

 an emulsion out of the fats ; that is to say, it breaks them 

 up into tiny particles and they become white like milk. 



Experiment 37. To show the action of pancreatic juice on the 

 albuminous ingredients (caseiti) of milk. Into a half-pint bottle (an 

 infant's nursing bottle will answer and is easily obtained) put two 

 tablespoonfuls of cold water; add one grain of pancreatin, and as 

 much baking soda as can be taken up on the point of a penknife. 

 Shake well, and add four tablespoonfuls of cold, fresh milk. Shake 

 again. Now set the bottle into a basin of hot water (as hot as one 

 can bear the hand in), and let it stand for about forty-five minutes. 



Take a small quantity of milk in a test tube, and stir in a few drops 

 of vinegar. A thick curd of casein will be seen. Upon applying the 

 same test to the digested milk, no curd will be made. The pancreatic 

 ferment (trypsin) has digested the casein into peptone, which does 

 not curdle. 



