82 ARTIFICIAL GASTRIC JUICE. [BOOK II. 



were singularly absent in the first observer. It was Schwann 1 who 

 pointed out how erroneous was the view of Eberle that mucin was 

 the principle which conferred proteolytic powers upon an acid infusion 

 of the mucous membrane of the stomach, by shewing that the active 

 principle held in solution in artificial digestive juice prepared by 

 the action of a dilute acid upon the gastric mucous membrane, had 

 properties which are different from those of mucin, and further that 

 by acting upon mucus obtained from other organs than the stomach, 

 a true digestive liquid cannot be obtained. 



Methods of 1. The stomach of a pig is opened, emptied of 

 preparing ar- its contents, and then the surface cleaned with a 

 tificial gastric we ^ S p OD g e ('running water' will dissolve out a con- 

 siderable part of the pepsin). The mucous membrane 

 is removed from all but the pyloric end of the organ. It is then 

 freed from a portion of the water which is adhering to it by 

 pressure between dry cloths, and minced. The finely divided 

 mucous membrane is then placed in two or three litres of dilute 

 hydrochloric acid containing from six to ten c.c. of strong HC1 per 

 litre, and the mixture is digested in the incubator at a temperature 

 of 35 45 C. for a period varying from a few hours to a day. If 

 sufficient fluid be present and the mixture now and then shaken, all 

 ought to be dissolved in a few hours, leaving but a small quantity of 

 brownish flakes and some mucus undissolved. The liquid is filtered 

 through paper, and then may be kept for several months, without 

 undergoing decomposition, and retaining active proteolytic pro- 

 perties. 



Artificial gastric juice prepared in this way is very energetic in 

 its action, and forty or fifty cubic centimetres added to 200 c.c. or 

 300 c.c. of 0*1 per cent. HC1 solution, will be usually found to furnish 

 a highly active digestive fluid. Such a juice does not, however, 

 contain merely acid and pepsin, but considerable quantities of albu- 

 moses and peptones. 



2. The following method was recommended long ago by Kuhne 2 

 for obtaining a juice possessed of considerable activity and yet contain- 

 ing but small quantities of peptones. Open the stomach soon after 

 death, empty it, and wash it thoroughly in cold water. Then scrape 

 the surface with a blunt instrument so as to remove a layer of mucus 

 mixed with epithelium cells. The matter thus removed is rubbed 

 up with pure quartz sand, or glass-powder, and cold water, which 

 dissolves the pepsin which the mixture contains. On filtering, an 

 opalescent liquid is obtained which, when acidulated so as to contain 

 O'l 0'2 per cent, of HC1, possesses powerful digestive activity. 



1 Schwann, 'Ueber das Wesen des Verdauungsprocess. ' Miiller's Archiv, 1836, 

 p. 90. 



2 Kiihne, Lehrbuch d. physiologischen Chemie. Leipzig, 1868, p. 33. 





