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PEACTICAL PHYSIOLOGY 



and glycerine in virtue of a lipase which is secreted by the gastric 

 glands. 



Method of Estimating Activity of Pepsin Solutions, (l) Grutzner's 

 Method (Approximate). Fibrin, purified as above described, is stained with 

 carmine solution, and washed free of adherent stain. Equal weighed quantities 

 are then placed in two test tubes, and 10 c.c. of 0'2 % hydrochloric acid are added 

 to each. Equal quantities of the pepsin solutions which it is desired to test are 

 added, and the tubes placed in the incubator. As the fibrin becomes digested the 

 carmine is liberated, and stains the solution. The more deeply stained solution, 

 therefore, contains the stronger ferment. The exact amount of carmine liberated 

 may be determined by comparing the digests with an artificial scale consisting of 

 ten solutions of carmine of different known strengths. A control of 0'2 % HCl 

 and carmine fibrin ought also to be studied. 



(2) Mett's Method. A narrow glass tube 1 to 2 mm. in diameter, and drawn 



1 Proteose B can be fractionated into various sub-varieties which differ from 

 one another in their elementary composition and somewhat in their reactions. 

 There is one variety of proteose B which gives no reaction with Millon's reagent. 



