EXAMINATION OF THE PANCREAS. 81 



long into a test-tube with a little leucine and one to two drops 

 of water. Heat till the alkali melts, when a strong evolu- 

 tion of ammonia takes place. Let cool, dissolve the melted 

 mass in a little water, and acidify with dilute sulphuric acid : 

 odor of valeric acid. Leucine by this treatment takes up 

 oxygen and is decomposed into ammonia, carbon dioxide, 

 and valeric acid. 



(c) Dissolve some leucine in water, decolorize the solution, 

 if necessary, with some good bone-black, filter, make alkaline 

 with caustic soda solution, and then add one to two drops 

 of copper sulphate solution: the precipitate of copper hy- 

 droxide, which first forms, dissolves to a blue solution of 

 leucine copper, which is not reduced on heating. 



3. The residue insoluble in alcohol, which has been freed 

 more or less completely from leucine, is treated with absolute 

 alcohol, filtered, and washed with alcohol and ether. Test 

 this for albumose and peptone by dissolving it in a little 

 water and saturating with ammonium sulphate, etc. (See 

 chapter on Gastric Digestion, page 33) . Ultimately the pep- 

 tone itself is to be isolated. 



II. DIASTATIC ACTION OF THE PANCREAS. 



Prepare some starch paste as follows : Measure off 100 cc. 

 of water, grind 1 g. of starch (potato-starch) in a mortar with 

 a part of the water, pour the fluid into a dish, rinse the mortar 

 with the rest of the 100 cc. of water, and heat the mixture to 

 boiling with constant stirring. Then treat 1 g. of pancreas- 

 powder with 50 cc. of water, digest for two hours at 40, and 

 filter. Mix in a test-tube equal volumes of the starch paste 

 and the pancreas extract, and digest at 40. The starch paste 

 liquefies and becomes transparent. At this point the solu- 

 tion gives the reaction for sugar and no longer turns blue on 

 the addition of iodine, but either turns red (erythrodextrin) 

 or gives no color at all. 



