410 BOTANICAL GAZETTE [MAY 
4. In some samples all, and in every sample more than 90 
per cent, of the total sulphur was in the organic form. ‘There was 
none or little sulphur present in excess of the actual needs as building 
material. 
This investigation was conducted under a research fellowship 
from the Gypsum Industries Association. The work was performed 
at the University of Chicago in the Hull Botanical Laboratory 
under the direction of Dr. W1LL1AM CrocKER. The writer wishes 
to thank the Gypsum Industries Association for their kindness in 
furnishing the fellowship, and Dr. Crocker for his advice and 
criticism. Thanks are also due Dr. FREDERICK Kocx for his advice 
and criticism of analytical methods. 
STATE NORMAL SCHOOL 
CHARLESTON, ILL. 
LITERATURE CITED 
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tion and quality. Ohio Agric. Exp. Sta. Bull. 285. pp. 173-209. 1915. 
. Brown, P. E., and Kextoce, E. F., Sulphur and permanent soil fertility 
in Iowa. Jour. Amer. Soc. Agron. 7:97—-108. 1915. 
3. CROCKER, WILLIAM, History of the use of gypsum as a fertilizer (unpub- 
lished). 
HAtverson, J. O., Estimation of sulphur in feeds and feces. Modified 
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N 
aD wu ne 
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Reports 1914, ~ oe 1917, 1918, 1919, 1920. 
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cal 
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