CHAP. III.]. 



THE DIASTATIC ENZYME. 



205 



Preparation 

 of a solution 

 of the pancre- 

 atic enzymes 

 in dilute alco- 

 hol (Roberts). 



, When discussing the methods of preparing active 



thodofprepar- "solutions of Trypsin, a method will be described where- 

 ing and pre- by the pancreatic tissue may be indefinitely pre- 

 serving the served, and active extracts obtained at any time, 

 pancreatic The method consists essentially in dehydrating the 

 finely divided pancreas by macerating it in alcohol, 

 and afterwards extracting with boiling ether. The insoluble residue 

 is exposed to the air, so as to allow the ether to evaporate, when 

 there is left a white friable solid mass, which may be powdered and 

 kept in a stoppered bottle for future use 1 . 



By digesting one part of dried pancreas at 40 C. for 3, 4 or 5 

 hours in 10 parts of a O'l solution of salicylic acid, extracts of great 

 activity may be obtained. 



One of the best methods of preparing a very active 

 solution of the pancreatic enzymes is the following, in 

 which advantage is taken of the fact that they are 

 very soluble in water and that their aqueous solutions 

 are preserved from decomposition by a small addition 

 of alcohol : 



Digest fresh pancreas freed from fat, and then chopped up, in four 

 times its weight of dilute alcohol, containing 25 per cent, of rectified 

 spirit (i.e. of alcohol of sp. gr. 0*838). The digestion is continued 

 for four or five days with occasional agitation. The mixture is then 

 filtered through paper. Filtration is much facilitated by the ad- 

 dition to the solution of 0*02 per cent, of acetic acid (containing 

 28 per cent, of the anhydrous acid). 



Degree of Activity and Mode of Action of a Solution of 

 the Diastatic Ferment. 



Following the last method, a solution may be obtained possessed 

 of remarkable activity, though this differs according to the animal 

 employed and its individual circumstances &c. The pig yields the 

 most active solution, its diastatic value being more than ten times 

 as great as that prepared from the pancreas of the ox or sheep. 



The action of the diastatic ferment of the pancreas 

 and pancreatic juice appears in essential particulars to 

 resemble that of the saliva and salivary glands ; i.e. 

 the products formed are the same, the conditions of 

 activity are similar, &c. According to v. Mering and 

 Musculus 2 in both cases there are formed achroodex- 

 trins, maltose and a little grape-sugar. 



1 Pancreas thus prepared may be obtained under the designation 'Pankreas, 

 trocken nach Kiihne,' from Dr Griibler, Bayersche Strasse 12, Leipzig, and is sold at 

 the price of Is. per 100 grammes. 



- v. Mering u. Musculus, 'Ueber die Umwandlung von Starke und Glycogen 

 durch Diastas, Speichel, Pankreas und Leber ferment.' Zeitschr. f.phys. Chem. Vol. n. 

 (187879), p. 403. 



Nature of 

 the action ex- 

 erted by the 

 diastatic fer- 

 ment of the 

 pancreas. 



