148 



PHYSIOLOGICAL CHEMISTRY 



Introduce into each tube a small piece of fibrin. Keep the tubes 

 at 4oC. and note the progress of digestion. Does the bile exert any 

 appreciable influence? How? 



10. Influence of Gastric Rennin on Milk. Prepare a series of five tubes as 

 follows : 



(a) Five c.c. of fresh milk -f 0.2 per cent hydrochloric acid (add slowly until 

 precipitate forms). 



Time 



I houi 



FIG. 44. CURVES SHOWING PSYCHICAL STIMULATION OF GASTRIC SECRETION 

 (Plotted from unpublished data in the author's laboratory by 

 Dr. Raymond J. Miller.) 



(b) Five c.c. of fresh milk + 5 drops of rennin solution. 1 



(c) Five c.c. of fresh milk + 10 drops of 0.5 per cent sodium carbonate solu- 

 tion. 



(d) Five c.c. of fresh milk -f 10 drops of a saturated solution of ammonium 

 oxalate. 



l Any good commercial rennin or rennet preparation may be used in preparing this 

 solution. 



