1 6 Bergman.— Relation of Aeration to Growth and Activity of 
Experiments with Impatiens balsamina. 
Two plants of Impatiens \ potted in soil, were placed in vessels of water 
so that the roots were completely submerged. Several plants of Philotria 
were placed in the water surrounding one of the pots. Aeration in this case 
was provided by the evolution of oxygen from the photosynthetic activity 
of Philotria . The second plant was in water without Philotria. Three 
days later the first plant was in good condition, while the second was wilted. 
The wilting of the second plant continued for two days more, when it was 
in such bad condition that it was removed. The first plant was still in good 
condition. This plant was left two months, during which time it lost about 
four or five leaves. Ten days after submergence of the roots new roots 
were com’ng out along the stem at the surface of the water. These con- 
tinued to develop, and an examination later showed that the lower roots 
had died, so that only the superficial ones were alive. 
The experiment with Impatiens was repeated later, six plants being 
used. All were potted in garden soil. Four of them were placed in water 
with the roots fully submerged. Of these four, one was aerated by bubbling 
air continuously through the water. Another was aerated by putting some 
Spirogyra in the water in which the potted plant was placed. The other 
two were not aerated. The fifth plant was grown in very wet soil. This 
was done by placing the pot in a basin of water so that only the bottom of 
the pot was in direct contact with the water. The sixth plant was grown 
in moist garden soil as a check. In three days the plants with the roots 
submerged in unaerated water were badly wilted and wer£ removed. All 
other plants were in good condition. In five days the plant in water 
aerated by bubbling air through the water showed a slight yellowing of 
some of the leaves, but no wilting. The plant aerated by Spirogyra was 
slightly wilted. This was assumed to be due to continued cloudiness, on 
account of which the liberation of oxygen by Spirogyra was reduced to 
such an extent that the water was insufficiently aerated. On the following 
day both plants in aerated water were badly wilted, the one in water 
aerated by Spirogyra being in the worse condition. Ten days after the 
experiment was begun the plants were still living, but each had lost several 
leaves. The remaining leaves were not wilted. Roots were beginning to 
develop along the stem at the surface of the water in both plants. The 
plants grown in soil wet by capillarity, and in moist garden soil, were in 
good condition. 
The experiment was allowed to run three weeks. All the plants except 
the two in unaerated water survived. Those with roots submerged in aerated 
water lost several leaves in the first week or ten days. After developing 
roots at the surface of the water, however, they began to grow again, and 
apparently normally. Roots below the surface died. Root-hairs were 
