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BEHAVIOR OF PLANTS IN UNVENTILATED CHAMBERS 29 1 
quiet air. The growth and general behavior were followed for the 
ensuing 10 days, but no differences could be detected. The seedlings 
began falling over from weakness 7 days after they had been placed 
in the cabinets. At this time, the largest seedlings in each pot were 
16 to 19 cm. high. Of the 38 seedlings in moving air, 9 showed 
primary leaves emerging between the half-open cotyledons; while 
among the 46 seedlings in quiet air, 1 1 showed primary leaves emerging 
between the opening cotyledons. At the end of 10 days in the dark 
cabinets, the most of the seedlings in each pot had fallen over. None 
were dead, and there was no damping off. 
The temperature during the experiment had ranged from 22° to 23°. 
Brassica alba seedlings, to the number of 72 in moving air and 63 
in quiet air, were grown in pots of earth, the preparations being placed 
in the two dark cabinets before the seedlings had broken through 
the ground. The plants grew in the two cabinets without showing 
noticeable differences, except that the cotyledons opened a little earlier 
in the quiet air; on the fifth day of the experiment, 12 seedlings in 
moving air and 16 in quiet air showed expanded cotyledons. On the 
sixth day, all but 8 seedlings in moving air, and all but 19 in quiet air 
had fallen over. The 10 longest hypocotyls in moving air averaged 
15 cm.; in quiet air, the 10 longest averaged 14.5 cm. There were no 
cases of damping off. 
The temperature had ranged for the 6 days from 22° to 23°, and 
kept the same in both cabinets. 
Cucurhita pepo L., with seedlings to the number of 63, gave the 
same general result as the foregoing species. Differences in behavior 
in moving and in quiet air in the cabinets could not be discerned. 
Sensitive Reactions in Ventilated and Unventilated Chambers 
Besides the criteria of the amount of growth, unfolding of leaves, 
and the vital period, used in the foregoing pages to estimate the effect 
of ventilation, it would be worth while to employ sensitive reactions 
also as a criterion. For this purpose geotropism and heliotropism 
have been studied with the plants in two small culture boxes, the one 
ventilated, the other closed against the exchange of air. These boxes 
were of wood 20 x 20 x 50 cm., with a closely fitting rabbeted door, 
and an aperture in one end 5 x 10 cm. The boxes stood side by side 
in a darkroom in which an electric fan was kept in constant motion. 
