X.] PANCREATIC DIGESTION. 83 



6. Putrefactive Products of Pancreatic Digestion. These include indol 

 skatol, phenol, volatile fatty acids, C0 2 , H 2 S, CH 4 , and H. 



,CH = CH 

 Indol 



Skatol 



Indol is one of the many putrefactive products of the decomposition of pro- 

 teids. Take equal parts of fresh fibrin and finely-divided ox-pancreas, add 

 ten times the volume of water, and keep the whole continuously at a tempera- 

 ture of 40 C. for three or four days. Intensely disagreeable-smelling gases 

 are given off. Strain through linen, acidulate (acetic acid), and distil the 

 filtrate. The filtered distillate is made alkaline by KHO or NaHO, and 

 shaken thoroughly with its own volume of ether. Distil the ether, and the oily 

 substance which remains behind, on being dissolved in water, is allowed to 

 crystallise. The solution yields the following tests. 



Tests for Indol. Use either the watery solution of indol or the 

 filtered offensive-smelling fluid before it is distilled. 



(a.) Warm the liquid, and add first a drop or two of dilute 

 sulphuric acid to some of the filtered liquid, and then a very dilute 

 nitrite solution. A red colour indicates the presence of indol. This 

 test is very readily obtained with the products of digestion by 

 Kiihne's dry pancreas (Lesson X. 1, e). One must be careful to 

 regulate the strength of the acid, as too strong nitrous acid prevents 

 the reaction. 



(&.) Acidify strongly with hydrochloric acid a small quantity of the highly 

 offensive fluid or the watery solution, and place in it a shaving of wood, or a 

 wooden match with its head removed and soaked in strong hydrochloric acid. 

 The match is coloured red, sometimes even an intense red. The match can be 

 dried, and it keeps its colour for a long time, although the colour darkens 

 and becomes somewhat duskier on drying. 



(c.) Chlorine Reaction. Add to some of the digestive fluid (5, 

 ft, preferably digest B), drop by drop, chlorine water; it strikes 

 a rosy-red tint. Or add very dilute bromine water (i to 2 drops 

 to 60 cc. water), the fluid first becomes pale red, then violet, and 

 ultimately deep violet (Kiihne). 



7. III. The Action on Fats is Twofold. 



(A.) Emulsification. 



(a.) Rub up in a mortar which has been warmed in warm water 

 a little olive-oil or melted lard, and some pieces of fresh pancreas. 

 A creamy persistent emulsion is formed. Examine the emulsion 

 under the microscope. Or use a watery extract of the fresh pan- 

 creas, and do likewise ; but in this case the result will not be nearly 

 so satisfactory. 



