March, 1922] NEWCOMBE — BEHAVIOR OF SENSITIVE STIGMAS II5 
closed. In one hour and three quarters, two stigmas were open 30° at the 
tips, the other two were closed. Five and three quarter hours after pollina- 
tion, all were closed. The next morning, 16 hours after pollination, all 
were closed. Many other tests made with living pollen show that this 
. result obtained with four stigmas is usual, and there can be no doubt that 
dead pollen is much less effective than living pollen in keeping the stigmas 
of Catalpa closed. 
To test the action of an enzyme directly, the commercial Taka-diastase 
was used on the stigmas of Catalpa and Torenia. Thirteen flowers of 
Catalpa, sitting in a httle water in the house, temperature 26°, moisture 
medium, had the Taka-diastase powder inserted into the angle of their 
divergent stigma lobes by using a little wooden rod whose tip was sharpened 
to a wedge. The stigmas closed immediately. After one hour, all were 
closed except one, which was well open. The same condition continued for 
6 hours, the time of the last observation of the day. The next morning, 
18 hours after the closing of the stigmas, 5 stigmas were open and 8 were 
closed. In another test, 10 stigmas of Catalpa, flowers treated as was the 
last set were given a mixture of one fourth Taka-diastase and three fourths 
starch. All stigmas remained closed for the rest of the day's observations, 
or for 6 hours. The next morning, 18 hours after the stigmas closed, 5 were 
closed and 5 were open. 
At the same time that the foregoing experiments were being conducted, 
II flowers of Catalpa, treated as were the other flowers, had pollen placed 
on their stigmas, and the stigmas closed. After 2 hours, 6 were open and 
5 closed. An hour later, 4 were open and 7 closed. The next morning, 
13 hours after poUination, 4 were open and 7 closed; but one that had been 
open the evening before was now closed, and one that had been closed was 
now open. This experiment was made as a control for the preceding. It 
here shows the diastase acting as well as the pollen in keeping the stigmas 
closed. The Taka-diastase is known to contain both diastase and hemicel- 
lulase. 
In an attempt to ascertain whether it was the enzyme content or the 
protein constitution of the Taka-diastase that kept the stigmas closed, the 
enzyme was destroyed by heating some of the powder in water at 80° and 
subsequently evaporating at a temperature of 50°. The resultant horny 
mass was powdered, but found to kill some of the stigmas when applied to 
them. Some of this powder was, therefore, mixed with three times its 
volume of corn starch, and the mixture was applied to the stigmas of 13 
flowers of Catalpa. The flowers were kept with their bases sitting in water 
in the house; the experiment was made the day following the preceding one. 
One hour after applying the mixture and closing the stigmas, all were still 
closed. Two hours after the beginning, all were closed; 5 hours after the 
be gmning, 6 were open and 7 closed; 9 hours after the beginning, 10 were 
open and 3 closed; 11 hours after the beginning, 10 were open and 3 closed; 
