FUNGOUS ROOT-TUBERCLES. 95 



Experiment VIII. 



To 50 cc. of dilute glycerin extract of Ceanothus tubercles 

 .25 gram of fibrin was added. A drop of chloroform was 

 added to each flask as an antiseptic. The temperature was 

 22°-23° C. 



Extract. After 14 hrs. After 24 hrs. 



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1. Normal. No action, fibrin No digestion. 



very loose. 



2. With 5 cc. 1% HC1. No digestion. Slight digestion. 



3. With5cc. l%Na 2 C03. No digestion. No change of fibrin. 



4. Heated to 80° C. A slight precipitate. No digestion. 



Extract. After 48 hrs. After 72 hrs. 



1. Normal. Some digestion. Considerable digestion. 



2. With 5 cc. 1% HC1. Liquid turbid. All digested. 



3. With5cc. l%Na 2 C03. No change of fibrin. No reaction. 



4. Heated to 80° C. No digestion. No reaction. 



Extract. After 96 hours. 



1. Normal. Only a few pieces undigested. 



2. With 5 cc. 1% HC1. All digested. 



3. With 5 cc. Na 2 C03. No reaction. 



4. Heated to 80° C. No reaction. 



Two other experiments with a similar extract were carried 

 on at 33° and 43° C. At 33° C. the results were similar to 

 those which were obtained at 23° C, whereas at 43° C. the 

 digestive activity was much slower. Hence the optimum 

 temperature for the enzyme is lower than 43° C. At 23° C. 

 there is no perceptible digestive action during the first thirty- 

 six hours, but following this period, the process goes on very 

 rapidly and in the normal and acid extract the fibrin is 

 readily digested. No fibrin was digested in the alkaline ex- 

 tract or in that which was heated to 80° C. Even 60° will 



stop the action of the enzyme. 



If my interpretation of the preceding data be correct 

 there is present, in the tubercles of the alder and Ceanothus, 

 an enzyme capable of digesting fibrin. The enzyme obtained 

 from the Ceanothus tubercles is more active at a lower tem- 

 perature than that from the alder which digests more readily 

 at a higher temperature. The enzyme, however, is found 



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