MarcH 8, 1912] 
iE. D. CLarK and F. J. SEAVER: Studies on Soils 
Subjected to Dry Heat. 
In the present paper we have extended to the 
green plants our earlier observations of the effects 
of heated soils upon the growth of fungi. Dif- 
ferent degrees of dry heat give soils whose aqueous 
extracts have a brown color the depth of which is 
proportional to the intensity of the heat. The 
amount of soluble matter, organic, inorganic, 
nitrogen, ete., was also proportional to the dif- 
ferent temperatures (90° to 180° C.). The. dark 
extracts from strongly heated soils were favorable 
for fungous growth but were distinctly unfavorable 
to Lupin seedlings grown in them; this inhibiting 
action being greatest in the darkest colored ex- 
tracts. Oats sown in a series of soils heated to 
different temperatures showed a slight stimulation 
for the temperature up to 125°, when compared 
with the unheated soil as a control; while above 
125° the heated soil had a very toxie effect. The 
organic matter of the darker extracts gives nearly 
all the tests for reducing sugars, is largely pre- 
cipitated by acetone, smells like caramelized sugar, 
and has a strong acid reaction to litmus. 
R. H. JESSE and Epwarp Bartow: Composition 
of Gases Formed by the Decomposition of Or- 
ganic Matter. 
We were called upon to investigate the cause of 
an explosion of gases in a septic tank at Highland 
Park, Illinois. In trying to trace the cause of this 
explosion we collected and analyzed gases from 
several septic tanks. But little variation was 
found between the composition of the gases from 
the tank which exploded at Highland Park and the 
gases from other tanks in the central west. There 
was, however, a great variation between the com- 
position of these gases and the reported composi- 
tion of gases analyzed by other investigators. 
During the summer of 1911 samples of gases were 
collected and analyzed from tanks in [Illinois, 
Columbus, Ohio, from Worcester, Massachusetts, 
and from the Illinois River below the mouth of 
the Drainage Canal. The greatest difference is 
seen in comparing the gases from Worcester with 
the gases from Illinois tanks. The gases from the 
Illinois River agree closely in composition with 
the gases from some of the septic tanks and differ 
very materially from a sample of gases collected 
from an unpolluted swamp. We have noted dif- 
ferences in gases taken from different compart- 
ments of the same tank and there is an apparent 
difference in gases collected below the upper sludge 
and in the bottom. 
SCIENCE 
389 
We feel that the results thus far obtained can 
only be regarded as preliminary to further study 
of the subject. 
E. D. Cuark and R. A. GortNER: The Chromogen 
and Associated Oxidases in the Mushroom Stro- 
bilomyces strobilaceus. 
L. A. Hawkins: The Effect of Certain Chlorides 
Singly and Combined in Pairs on the Activity of 
Malt Diastase. 
R. A. GORTNER and EH. D. Cuark: The Chromogen 
and Associated Oxidase in the Mushroom, Stro- 
bilomyces strobiloaceus. 
Upon injury the color change of this fungus is 
from white through pink to black, this action 
being a rapid one. We considered that this was a 
case of ordinary tyrosinase activity and it was 
only upon examining the material for another pur- 
pose that we learned that this assumption was not 
true. We were unable to detect the slightest trace 
of free tyrosin by any of the delicate color tests. 
However, we were able to make preparations of an 
oxidase from this plant that were very active in 
causing the oxidation of a tyrosin solution. Evi- 
dently, then, this fungus contains a tyrosinase or 
similar enzyme which oxidizes some other chromo- 
gen. This chromogen proved to be pyrocatechin 
or one of its derivatives, as shown by all the tests 
and methods at our disposal. The oxidase prepa- 
ration produced exactly the same change in a solu- 
tion of pure pyrocatechin that is noticed in the 
plant itself. 
H. H. BunzeEut: Biochemical Study of the Curly- 
top Disease of Sugar Beets. 
The paper gives results obtained in oxidase 
measurements on diseased and healthy beets, on 
leaves as well as roots, under the various condi- 
tions at different times of the day and various 
stages of development. The result obtained in 
greenhouse experiments, 7%. e., that the diseased 
leaves have a higher oxidase content than the 
healthy ones, was confirmed in the field. The gen- 
eral result of all the experiments carried out, indi- 
cates that the oxidase content is higher in the 
leaves in all the cases where the normal growth of 
the plant has been interfered with, whether the 
retardation of growth is brought about by exces- 
sive drought, excessive watering of the soil, the 
eurly-top disease or other diseases. The distribu- 
tion of the oxidase in the leaves and roots of the 
plant was measured. Analyses of the samples 
collected simultaneously with the oxidase deter- 
minations are as yet not completed. 
