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 HCl only the Gramineae showed activity. When Na 2 Co 3 
was left out, apple, daisy (?), and dock were added to the list. ThCvSe 
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 I percent Witte's peptone, 2 cc. of N/io sodium carbonate, 5 cc. of pollen 
extract 50 mg. in 10 cc. (unheated and autoclaved), 100 mg. of thymol. 
2. 10 cc. of i/io per cent Witte's peptone, i cc. of N/io 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 CUSO4 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, i 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: (i) i cc. peptone solution, or peptone 
plus Na2C03, and thymol. (2) i cc. peptone, or peptone plus Na2C03 plus 
unheated pollen, and thymol. (3) i cc. peptone, or peptone plus Na2C03 
plus autoclaved pollen. 
The sixteen varieties of pollen previously listed were tested, but only 
apple arid 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 dift'erent kinds 
of pollen was tested. All showed some reducing action; apple, Austrian 
pine, and magnolia were especially active. Apple pollen changed KMn04 
