732 
Journal of Agricultural Research 
Vol. V, No. 16 
From these experiments there can be little doubt that pycnidia can 
be produced by this fungus without reference to the factor of transpira¬ 
tion. 
We now come to an experiment in which the time element was recorded 
and in which the influence of a number of different degrees of air humidity 
was tested. 
Four bell jars with a hole in the top were connected with a compressed- 
air reservoir so that a gentle current of air could be sent through the 
apparatus. The air was led into the bell jars by a tube reaching to 
the bottom of the bell jar and taken out by short tubes which extended 
through the stopper but a short distance. To secure moist conditions 
the air was bubbled through distilled water, while dry air was obtained 
by sending the blast through two towers filled with calcium chlorid. 
The first bell jar received moist air constantly, the fourth dry air con¬ 
stantly, and the second and third were connected by Y tubes to both 
the dry and wet bell jars, so that they could be made to receive either 
wet or dry air independently. Throughout the experiment the condi¬ 
tions in these two bell jars were alternated. The second bell jar received 
wet air for three days and then dry air for one day, while the condi¬ 
tions were reversed for the third jar. Preliminary tests with a Lamp- 
recht poly meter in each jar (these were set to agree with a sling 
psychrometer reading) showed that the humidity within the first jar 
ranged from 65 per cent to 70 per cent, and in the fourth the humidity 
was only 20 per cent. In the other bell jars a humidity of 65 per cent 
or a dryness corresponding to 25 per cent could be obtained in a half 
hour by blowing in wet or dry air. The blast was almost continuous 
throughout the experiment except for a period each day between about 
3 a. m. and 8 a. m., at which time the pressure was lacking. The bell 
jars giving wet conditions were fogged at times, but, as the apparatus 
was in strong light and as the fog disappeared except when the bell 
jars were hit by a cold draft, it is very likely that the light intensities 
were sufficient in all cases. For media various substances were used. 
Bits of pear and apple twigs, com meal, slices of carrot and apple, peas, 
rice, and corn, as well as corn-meal agar and glucose agar, were auto¬ 
claved. The media were prepared in capsules without the covers and 
were placed in tiers in round wire baskets so that each capsule had free 
access to air. The basket was slipped inside a battery jar and was 
covered with a cotton pad held in place by a glass plate. Five sets of 
this sort were prepared, four to be subsequently placed under the bell 
jars, and the fifth to be used as a check without aeration. The media 
were autoclaved and then inoculated with a drop of spore suspension 
to each dish. The cultures were left one week under ordinary room 
conditions. At the beginning of the test of the various air conditions the 
bell jars were drenched with solution of mercury bichlorid. The basket 
was lifted under aseptic precautions and set upon a small metal rack. This 
