Dec, I92i] PATON — POLLEN AND POLLEN ENZYMES 489 
due to the action of invertase. Moreover, apple pollen, which was found 
to contain sucrose, was extremely active in its invertase reaction. The 
results are shown in table 12. 
Table 12. Tests for Invertase 
Kinds of Pollen Active Pollen Control 
Easter lily pollen Rapid reduction Slight reduction 
Lilium ruhrum Slow " " " 
Red maple Very rapid reduction " " 
Norway maple Rapid reduction - " " 
*Apple Instant " Some after 20 min. heating 
Austrian pine Slow but marked Slight reduction 
Scotch pine << << a a 
Magnolia Very rapid " " 
Dandelion Slow but marked " " 
Tests for Lipase 
In the different methods used for testing for lipolytic enzymes the fol- 
lowing substrates and testing reagents were used : 
1. Substrates. 
(1) Ethyl butyrate. 
(2) Olive oil acidified with decinormal acetic acid and a little gum 
arable added to make an emulsion. 
(3) Olive oil emulsion recommended by Zeller. 10 cc. of olive oil 
was dissolved in hot 100 percent alcohol. This was run through 
a hot separating funnel to which was attached a piece of glass 
tubing drawn out to a capillary jet. The stream of oil in alcohol 
was run into 100 cc. of cold distilled water which was stirred 
continually. The milky emulsion was then heated to drive off 
the alcohol and afterwards diluted with water. 
(4) Methyl acetate. 
2. Activator. Approximately N/60 oxalic acid was used, partly because 
free acid is needed to counteract the slight alkalinity of the ground glass 
and more especially because free acid accelerates the activity of lipase. 
3. Alkali for titration. Approximately N/io sodium hydroxid solution 
was used to which a trace of barium hydroxid was added. To insure uni- 
formity in readings, a 3-liter bottle was filled, and the solution was drawn 
off as needed through a connected graduated burette. Both the bottle and 
the burette had soda-lime bulbs at the inlet to absorb CO2. 
4. Indicator. Phenolphthalein was used in all titrations as an indicator. 
5. Antiseptic. Toluol was added as an antiseptic. Controls of auto- 
claved pollen extract were run in each case, and the digestions were carried 
on in small stoppered Erlenmeyer flasks kept in an electric incubator at 36°- 
38° C. Samples were titrated at different time intervals. Methyl acetate 
was more strongly hydrolyzed than either ethyl butyrate or the olive oil 
preparations. 
