424 HEPBURX— BIOCHEAIICAL STUDIES 



The pitcher liquor did not contain a diastase. The Hquor was mixed 

 with a thin starch paste, and then incubated for 24 hours at 20° to 30° C. 

 The starch was not hydrolyzed, the filtered solution was optically inac- 

 tive, and did not reduce FehUng solution, hence did not contain reducing 

 sugar. 



Sufficient liquor from stimulated pitchers was not available to deter- 

 mine the nature of the free acid present in it. It is stated that hydro- 

 chloric acid may be excluded. 



Liquor from N on- stimulated Pitchers 



Gelatinous, swollen fibrin was washed until the acid reaction (due to 

 hydrochloric acid) had almost completely vanished. Flocks of the 

 fibrin, which were placed in the liquor, suffered no noticeable change with- 

 in several hours at 20° to 30° C, and had not dissolved to the shghtest 

 extent at the end of 24 hours; the fibrin had contracted somewhat, and 

 the filtrate from it gave a scarcely noticeable tinge of rose-red in the 

 biuret test. However, the fibrin was almost completely dissolved in 

 13/^ hours by pitcher liquor to which 2 or 3 drops of 0.2 percent hydro- 

 chloric acid had previously been added; the resulting solution behaved 

 in every way as did the solution obtained by the action of the acid liquor 

 from stimulated pitchers. 



Swollen fibrin, carefully freed from adherent hydrochloric acid, was 

 dissolved almost instantaneously at the ordinary temperature by liquor 

 to which 3 or 4 drops of dilute formic acid had previously been added. 

 The residue, which was scarcely noticeable, was removed by filtration, 

 and the filtrate was carefully neutralized. The very shght precipitate 

 which formed was collected on a filter; the filtrate gave none of the react- 

 ions of the true proteins, but did give an intense biuret reaction. When 

 the formic acid was replaced by acetic acid, or by propionic acid, the 

 fibrin was digested less rapidly, the rate of digestion now being about the 

 same as in the liquor of the stimulated pitchers. At a temperature of 20° 

 to 30° C, the fibrin was completely dissolved in 2 to 3 hours; the resulting 

 solution contained mainly metaproteins and gave a very faint biuret 

 reaction. 



When the pitcher liquor was previously acidified with malic acid, the 

 fibrin was almost completely dissolved in 10 minutes at ordinary tempera- 

 ture; the resulting solution gave a faint but distinct biuret reaction. 

 After the digestion had been in progress for 2 hours, the precipitate on 

 neutralization was very slight, and the biuret reaction decidedly more 

 marked. When citric acid was substituted for malic acid, the fibrin was 



