Dec, 1921] PATON — POLLEN AND POLLEN ENZYMES 493 



alkali. It may also be noted that in the digestion of fibrin in the presence 

 of 0.2 percent HC1 only the Gramineae showed activity. When Na 2 Co 3 

 was left out, apple, daisy (?), and dock were added to the list. These 

 tests were repeated several times and gave consistent results. Toluol was 

 substituted for thymol without any noticeable difference. In no case was 

 there the slightest odor of putrefaction. The antiseptics were easily de- 

 tected by their odor. 



Tests for Erepsin 

 Solutions of Witte's peptone were used in the following proportions: 



1. 10 cc. of 1 percent Witte's peptone, 2 cc. of N/10 sodium carbonate, 5 cc. of pollen 

 extract 50 mg. in 10 cc. (unheated and autoclaved), 100 mg. of thymol. 



2. 10 cc. of 1/10 per cent Witte's peptone, 1 cc.of N/ 10 sodium carbonate, 10 cc. of pollen 

 extract (unheated and autoclaved), 100 mg. of thymol. 



3. The above described solutions were used without adding sodium carbonate. 



For testing, Gies's biuret reagent was used. This reagent consists of 

 10 percent KOH solution, to which 25 cc. of 3 percent CuS0 4 solution per 

 liter is added. A large flask was filled with the reagent and connected with 

 a graduated burette so that for each test the same strength of reagent should 

 be used. In making the tests, 1 cc. of the solution to be tested was put 

 with 20 cc. of biuret reagent in 25 cc. Nessler comparator tubes of uniform 

 diameter and thickness. The color differences were read by looking down 

 through the liquid at a white background. Solution 2 proved the best 

 dilution. More than I cc. of the pollen-peptone solution did not give 

 satisfactory results because of color interference and turbidity. In each 

 test three tubes were compared: (1) 1 cc. peptone solution, or peptone 

 plus Na 2 C0 3 , and thymol. (2) 1 cc. peptone, or peptone plus Na 2 C0 3 plus 

 unheated pollen, and thymol. (3) 1 cc. peptone, or peptone plus Na 2 C0 3 

 plus autoclaved pollen. 



The sixteen varieties of pollen previously listed were tested, but only 

 apple and magnolia pollen gave positive results. Here the reaction of the 

 unheated pollen with the biuret reagent gave a very faint pinkish tint as 

 compared with the rose-violet tint of the controls. 



Tests for Catalase 



The decomposition of hydrogen peroxid in a fermentation tube was used 

 as an indication of a catalase. All the kinds of pollen tested showed a 

 marked reaction. Easter lily, magnolia, and apple pollen were exceedingly 

 active. Maple pollen was the slowest but the action was evident. The 

 boiled pollen extracts did not give the reaction. 



Tests for Reductase or a Reducing Substance 

 The reduction of potassium permanganate solution by the different kinds 

 of pollen was tested. All showed some reducing action; apple, Austrian 

 pine, and magnolia were especially active. Apple pollen changed KMn0 4 



