G. MCGUIRE AND K. G. FALK 443 



in the gel formations with time and concentration of salt with the 

 first three salts were similar to those already given. 



IV. The Action of Pancreatine on Banana Extract. 



As a result of some experiments carried out for a different purpose, 

 the formation of a gel by the action of pancreatine on banana extract 

 was observed. For example, one 40 cc. portion of banana sodium 

 chloride extract was treated at pH 5.0 with 0.2 gm. of a commercial 

 pancreatine preparation, and another with 0.1 gm. In 24 hours at 

 38°, the former formed considerable gel, the latter formed less gel. 

 At 5°, the same mixtures produced no gels. If either the pancreatine 

 or the extract was boiled before mixing the solutions, no gel was 

 obtained. The gel which was obtained by the action of the pan- 

 creatine appeared to be less firm than that obtained by the action of 

 calcium salts. 



A number of the gels prepared by dialysis were filtered on paper, 

 washed with alcohol and ether and dried and analyzed. The analyses, 

 however, mean nothing. The gels as obtained carried down mechani- 

 cally or otherwise much of the dissolved material present. Attempts 

 to wash the gels with water were not successful, swelling occurring 

 in almost every case. Until methods of purifying the gels, or at 

 least of removing extraneous material are developed, nothing definite 

 can be stated relative to their chemical composition. It may be 

 mentioned, however, that the nitrogen content of the dried gel was in 

 the neighborhood of 4.5 per cent, pointing to the presence of about 

 25 per cent protein material. 



DISCUSSION. 



The question of the relation of this work to other work of similar 

 nature can be disposed of briefly. The source of the material and 

 some of the reactions may indicate that the gels are of the nature of 

 pectins.^ However, against this view are the facts that boiling de- 

 stroys the gel-forming property and that only very small quantities 

 of calcium and strontium salts are required to yield the gels under 

 suitable conditions. 



« CJ. Hayncs, D., Biochcm. J., 1914, viii, 553. 



