54 BOTANICAL GAZETTE [SEPTEMBER 
a close connection between the nitrogen and chlorophyll content 
of Coleus leaves, so that it is possible that sulphur has at least part 
of its effect through increasing the nitrogen content of the plant. 
My work seems to indicate this, but more work is desirable before 
coming to any definite conclusions. In the case of the non- 
legumes, the activity of ammonifying and nitrifying bacteria of the 
soil might be increased. The evidence is conflicting as to the 
effect of sulphur on these organisms, some claiming a favorable 
effect and some little effect. It is hoped to repeat this experiment, 
both in the case of corn and clover, omitting the nitrates entirely 
or keeping them very low. This should be done from the start; 
then, if the sulphur does have its effect indirectly by increasing 
the nitrogen supply through an increase in the number and activity 
of these organisms, this effect should be apparent. Special pre- 
cautions should be taken to exclude sulphur. Sulphur-free salts, 
of course, should be used. The sand should be thoroughly washed 
with distilled water, perhaps even boiled in acid and then washed 
with distilled water, to eliminate any sulphur that it may contain. 
If decided differences in color develop, as a result of sulphur — 
deficiency, the microchemical analyses should be followed by 
quantitative chemical analyses. 
Table XI gives data concerning the effect of sulphur in different 
forms and different amounts on the growth of sweet corn. As | 
before stated, the. corn was grown with the idea of obtaining 
material to study the effect of sulphur on chlorophyll development 
in non-legumes. Since no difference in color in the different 
series developed, the corn was harvested and the dry weight 
determined, to see the effect of sulphur on the growth. It had 
been growing about two and one-half months and was in tassel. 
The details of the plan of the experiment have already been given. 
The numbers in the column ‘‘Treatment” indicate that flowers of 
sulphur and sodium sulphate were added in such amounts as to 
contain the same amount of sulphur as present in 100, 300, or 500 
pounds of gypsum per acre, or two million pounds of sand. The 
percentage increase or decrease is based upon the dry weight. 
The minus sign indicates a decrease. 
Series 4 should not be considered, for from the first the corn 
in two of the pots of this series did not grow well. At the time of 
