II 
Journal of Agricultural Research 
Vol, XXIV 
Influence of Temperattire on the Spore Germination of Ustilago zeae. Edith Page 
Seymour Jones (i text figure). 593 
Spores in the Upper Air. Edvin C. Stakman, Arthur W. Henry, Gordon C. 
Curran, and Warren N. Christopher (2 plates).... 599 
Studies on the Life History of Stripe Rust, Pticcinia glumarum (^hm.) Erikss. 
and Henn. Charges W. Hungerpord (i text figtu^; 4 plates). 607 
Influence of Some Nitrogenous Fertilizers on the Development of Chlorosis in 
Rice. L, G. Wilus and J. O. Carrero.:.. 621 
Some Graminicolous Species of Helminthosporium; I. Charles Drechsler 
(33 plates)........... . 641 
Omtrol Snow Molding in Coniferous Nursery Stock. C. F. Korstian (3 plates) 741 
An Influence of Moisture on Bean Wilt. L. T. Leonard (3 plates). 749 
The Pseudo-Antagonism of Sodium and Calcium in Dilute Solutions. H. S. 
Reed and A. R. C. Haas (i plate)... 753 
Influence of the Hydrogen-Ion Concentration on the Growth and Fixation of 
Nitrogen by Chdtures of Azotobacter. P. L. Gainey and H. W. Batchelor 
(itextfigme). 759 
Sunflower Investigations. Ray E. Neidig and Robert S. Snyder. 769 
Effect of Different Concentrations of Manganese Sulphate on the Growth of 
Plants in Acid and Neutral Soils and the Necessity of Manganese as a Plant 
Nutrient. J. S. McHargue (2 plates). 781 
Sweet Qover Investigations. Ray E. Neidig and Robert S. Snyder. 795 
Growth and Composition of Oran^ Trees in Sand and Soil Chiltures. H. S. 
ReE 9 and A. R. C. Haas (5 iflates).... 8oz 
Further Studies on the Inheritance of **Rogue'* Types in Garden Peas (Pisum 
sativum L.). Wilber Brotherton, Jr. (3 text figures; 8 plates). 815 
A Method of Treating Maize Seed to Destroy Aonerent Spores of Downy 
Mildew. William H. Weston, Jr... 833 
influence of the Substrate and its Hydrogen-Ion Concentration on Pectinase 
Production. L. L. Harter and J. L. Weimer . 86z 
The Microscopic Estimation of Colloids in Soil Separates. William H. Fry. . 879 
Morphology and Host Relations of Pucciniastrum americanum, B. O. Dodge 
(5 plates)..... 88$ 
Watc^-Rot oi Tmnato Fruits. Fred J. Pritchard and W. S. Porte (4 plates). 895 
Influence of the Absolute Reaction of a Soil upon its Azotobacter Flora and Nitro- 
gen-Fudi^ Ability. P. L. Gainey (i text figure). 907 
A Study icff Factors Affecting the Nitrogen Content 01 Wheat and of the Changes 
that Occur during the Development of Wheat. George A. Olson (2 text 
figi^)....... —. 939 
Relative Susceptibility of Citrus Fruits and Hybrids to Cladosporium citri 
Massee. G. L. Peltier and W. J. Frederick. ... 955 
An Improved Method for the Determination of Nicotine in Tobacco and To¬ 
bacco Extracts. O. M. Shedd.... 961 
Nutritive Value of Mixtures of Proteins from Com and Various Concentrates. 
D. Breese Jones, A. J. F^nks, and Carl O. Johns (7 text figures).... 971 
The Mode of Inheritance of Resistance to Pucctnia graminis with Relation to 
^ed Color in Crosses between Varieties Durum T^eat. J. B. Harrington 
and O. S. Aamodt (4 plates)..... 979 
A Study of Rust Resistance m a Cross between Marquis and Kota Wheats. 
H. K. Hayes and O. S. Aamodt (3 plates) .. ... 997 
Biologic Forms of Pucdnia graminis on Varieties of Avena Spp. E. C. Stak¬ 
man, M. N. Levine, and D. L. Bailey (4 plates).... 10x3 
Disease Resistance to Onion Smudge. J. C. Walker (4 text figures; 4 plates). 1019 
The Effect of Respiration upon the Protein Percentage of V^eat, Oats, and 
Barley. F. W. McGinnis and G. S. Taylor. 1041 
ERRATA AND AUTHORS' EMENDATIONS. 
Page xo<S!. line zo, should read “western yellow pine (P. Ponderosa Lawson, var. scopulomm Eng.), 
Douglas fa iPseudotsuga taxifolia [I,ambertJ Britt.), lodgepole pine (P,amtartat Loud., —P. murravana 
Ball.), and Engelmann spnice (P. engelmdnni [Parry] Eng.), instead of “ western yellow pine, Douglas 
fir, lodgopole pine, and Engdinann spruce,’’ 
Page 106, line 13, should read “ Lake States pines (White pine, P. strobus Linn., Norway or red inne, 
P. resinosa SoL, and Jack pine, P, droarifota Gordon) and” instead of ** Lake States pines and.’’ 
Page X95, footnote s, thi^ line from bottom, insert alter the words “ sour orange ” the following: **Citrus 
pontelo.” 
Page asx, line ii, should read “bactericidal” instead of “bacteriaddal.” 
Pare*53.line* 15 to x 6 from bottom, should read **Andropogon scoparius*’ instead of ’ Andropogon 
Scqpiafus. ' 
Jrage 443, line s, should read “they produced” instead of “they provided.” 
Page 897, Table I, head “Fruits inoculated” should stand over columns 2, 3, 4, 5, Head “Fruits in¬ 
fected” should stand over columns 6 to 13. 
