ACTIVITY OF CATALASE PREPARATIONS 557 



a title is superfluous and for this reason has had but little 

 recognition. 



Demonstration. F. Battelli and L. Stern have developed 

 a method by which catalase preparations of extremely 

 marked activity may be obtained. It is best to make use of 

 horse-liver or beef-liver, which is finely divided, agitated 

 with water for a long time and strained; the fluid is then 

 precipitated with alcohol, the precipitate separated and 

 redissolved in water, and the solution again precipitated 

 with alcohol. 



Finally there is obtained an amorphous powder of almost 

 incredible catalyzing power. One gram is capable of break- 

 ing up, in ten minutes at room temperature, four kilograms 

 of hydrogen peroxide with production of 1300 liters of 

 oxygen. The preparation is quite permanent and may re- 

 tain its activity unchanged for years. It is well known that 

 a number of colloidal metals (as platinum, palladium, 

 iridium and osmium) are also capable of manifesting ex- 

 tremely powerful catalyzing influence. It is calculated that a 

 solution of osmium containing not more than 0.000,000,000,9 

 gram of osmium in a cubic centimetre, is still capable of 

 disintegrating hydrogen peroxide appreciably. 2 Neverthe- 

 less Battelli and Stern believe (particularly when the pre- 

 sumably great molecular weight of the catalase is taken 

 into consideration) that the activity of their catalase is 

 infinitely greater than that of colloidal platinum. 



Determination of Activity of Catalase Preparations. 

 Determination of the activity of a catalase preparation may 

 be carried out in different ways. A given quantity of tissue 

 or of a preparation to be tested may be allowed to act upon 

 a known quantity of hydrogen peroxide, and after a certain 

 time the amount of oxygen formed may be determined or 

 the quantity of remaining unchanged peroxide of hydrogen 

 may be estimated. Or a dynamic method may be used, by 



2 C. Paal, with C. Amberg and J. Gerum, Ber. d. deutsch. chem. Ges., 40, 

 2201, 2209, 1907. 



