273 
CONFERENCE NOTES. 
The first of the autumn conferences was held in the library on 
Monday, November 7, Dr. N. L. Britton presiding 
Dr. E. D. Clark discussed the results of work on the soluble 
substances in soils resulting from exposure to dry heat, which 
study is a continuation of work reported last year.* The fol- 
lowing is a synopsis of the paper prepared by Dr. Clark. In 
these later studies we have extended to the higher plants our 
observations on the effects of heated soils upon the growth of 
fungi. We had previously noticed that the color of soil extracts 
seemed to vary with the temperature to which the soil had been 
subjected, the higher temperatures causing darker extracts. 
matter than those of lighter color. In other words, the amount 
of matter made soluble by heat depended upon the intensity of 
the heat and to this, the color of the extract served as an index. 
The highly colored extracts always proved favorable as a medium 
for Pyronema and other fungi. On the other hand, experiments 
with lupine ae indicated that they were affected in an 
unfavorable way by the heated-soil extracts, especially by those 
from soils exposed to high temperature and consequently having 
much material in solution. Those extracts most favorable to 
the growth of fungi were most unfavorable to the growth of 
green plants. 
Oats were sown on a series of soils already exposed to different 
temperatures and the effects of the various soils noted 
soils which were heated to 90° C. and 120° C. seemed to show 
slight stimulation of growth over that of the control on unheated 
soil. However, the soils heated to 150° C. and 170° C. had a 
marked inhibiting action upon the oat seedlin: 
Coville has found that certain plants a. as the blueberry, 
etc., are lovers of acid bog-soils and only reach their best develop- 
ment under such conditions. We wish to determine whether the 
* Studies in Pyrophi ilous Fungi—Il. Changes br rought a about by the heating 
of soils and their relation to the growth of Pyronemu and other fungi. Mycologia 
2: 109-12, IQL0. 
