THe NATURE AND REACTION OF WATER FROM HyYDATHODES 1 
no bubbles. The bubbles were taken as an indication of the presence 
of catalase. The test was positive when made with exudate water col- 
lected from sterile oats, maize, and timothy. 
Peroxidase.— In making the first test for peroxidase, 5 cubic centimeters 
of the exudate water from maize was placed in a test tube and about 0.1 
cubic centimeter of hydrogen peroxide was added. The solution was 
mixed thoroughly and allowed to stand for from two to three minutes. 
After this interval a few drops of a five-per-cent phenol solution was added. 
If peroxidase was present, a browning of the solution occurred and after 
a time a precipitate settled to the bottom of the test tube. This reaction 
~ was very decisive. The browning began within ten seconds after the test: 
was made, and was accompanied with a heavy brown precipitate. When 
a similar test was made using boiled exudate water, no reaction was 
obtained. — 
Tests with water from hydathodes of sterile maize eight days old and 
oats nine days old were also very decisive, while a test from timothy 
seven days old was negative and one from plants ten and thirteen days 
old was positive. ; 
In a second test for peroxidase, two drops of hydrogen peroxide was 
added to about 3 cubic centimeters of the exudate water from maize, 
and the materials were mixed. In about one minute two drops of an 
alcoholic solution of guaiac was added. There was instantly a bluing 
of the guaiac, the blue color becoming intense. This did not occur if 
hydrogen peroxide was omitted or if the exudate water was boiled. This 
test was positive when made with exudate water collected from sterile 
maize, oats, and timothy. 
Reductase.— Klein (1913) reports that no nitrites were found in water 
from the leaves of Boehmeria utilis and Fuchsia sp. when it was examined 
immediately after being excreted, but that they appeared after from 
six to eight hours, and that on longer standing ammonia developed. 
This loss of nitrates and subsequent appearance of nitrites and ammonia 
Klein ascribed to the action of molds and bacteria. It would seem that 
there are other possibilities in such a reduction. Nitrate-reducing enzymes 
are found in many plants, and, since exudate water has been in contact 
with living cells of the roots, the stems, and the leaves, it may have in 
it the power to reduce nitrates to nitrites and ammonia. 
In a test to determine the presence of reductase, exudate water was 
collected from sterile timothy plants eighteen days old. The materials 
were used in the following proportions: 10 cubic centimeters of exudate, 
2 cubic centimeters of a 50-per-cent solution of NaNOs, 0.1 cubic centi- 
meter of benzyl alcohol as an accelerator, 0.9 cubic centimeter of water. 
As a control, the 10 cubic centimeters of exudate was replaced by boiled 
exudate water. These materials were placed in a stoppered container 
and thoroughly mixed. The test and the control were kept at about 
37° C. for forty-eight hours. At the end of this time the presence of 
nitrites was determined with the Griess reagents. It is presumed that 
these conditions were not favorable for bacterial growth. 
A comparison of the solutions showed at least twice as much nitrite 
in the test as was found in the control. A somewhat similar test con- 
ducted for twenty-four hours, in which exudate water from sterile timothy 
