44 



change of color occurs in the one with the pancreas, due to 

 the formation of fatty acids by the enzyme steapsin. A fresh 

 watery extract of the pancreas also acts favorably. 



147. Another form of the experiment is to mix the oil with finely divided 

 perfectly fresh pancreas in a mortar, and keep it for a time at 40°C. It soon 

 becomes acid, owing to the formation of fatty acids. Test with litmus paper. 



148. Action on milk. Dilute 2 cc. of cow's milk with 10 

 cc. of distilled water in a test tube and add 5-6 drops of pan- 

 creatic extract. Keep at 40°C. from J^ to 1 hour. Note any 

 chang-e that has occurred. 



149. Divide the above into two parts. To one part add 

 a little dilute acetic acid ; if there is no precipitate it indicates 

 that the caseinogen has been converted into peptones. To the 

 other part apply the biuret reaction for peptones. 



150. With the reserved portion from the albumin and 

 fibrin tubes, (138), indol may be found if digestion has con- 

 tinued long enough and if an offensive odor be present. To 

 some of the suspected fluid add 1 cc. of 0.01% solution of 

 sodium or potassium nitrite (fresh) and then a few drops of 

 concentrated sulphuric acid. A pink color indicates the pres- 

 ence of indol. 



151. Food test. Use the two digestive extracts furnished. Try the activity 

 of each upon some fibrin and starch solution in an acid (0.2% HCl) medium, 

 and also in an alkaline (1% NajCOa) medium at a temperature of 38 to 40 deg. 

 C. Determine in which medium the best results are obtained and identify the 

 extract. 



Test with the extracts the foodstuff provided. Determine if there is pro- 

 teolytic digestion, by testing for acid or alkali albumin, albumose, peptone 

 and indol. 



Determine if there is amylolytic digestion by testing for dextrin and dex- 

 trose. 



In addition to the extracts furnished for the experiments, collect your own 

 saliva and try its amylolytic action upon the foodstuflf. 



152. Valuation of Commercial Pepsin. Dissolve 67 mg. of the pepsin in 

 100 cc. of 0.2 fo hydrochloric acid. 



Add 5 cc. of the above solution to 95 cc. of 0.2% hydrochloric acid. Place 

 lOcc of this diluted pepsin sol. in 1 test tube, 15 cc. in a 2nd, 20 cc. in a 3rd, 25 cc. 

 in a 4th, 30 cc. in a 5th tube. Place all in a water bath at 38-40 degrees C. 



Place an egg in boiHng water and boil for IS minutes, then place it in cold 

 water. When cold, wipe it dry, remove the coagulated albumin and rub it 

 through a No. 30 sieve. 



Place 1 gram of this disintegrated albumin in each of the above test tubes 

 at 38-40 degrees and shake well, to thoroughly mix, being careful not to lose 

 any of the solution or albumin. Keep at 38-40 degrees for six hours, gently 

 shaking the tubes every 15 minutes. 



