j, "DISEASED 
JOWAL OF MClim RESEARCH 
Vol. XXXI Washington, D. C., July 1-December 15, 1925 
CONTENTS 31 WO 
Page 
Further Studies on the Overwintering and Dissemination of Cucurbit 
Mosaic. S. P. Doolittle and M. N. Walker (6 plates; 1 text figure) 1 
Preliminary Report on Colloidal Clays as Emulsifiers for Mineral Oils 
Used in Spraying Citrus Groves. W. W. Yothers and John R. 
Winston_ 59 
Relation Between Certain Heritable Properties of Wheat and Their 
Capacity to Increase Protein Content of Grain. W. F. Gericke_ 67 
Spreaders for Spray Materials, and the Relation of Surface Tension of 
Solutions to Their Spreading Qualities. R. H. Robinson_ 71 
Associations between Number of Kernel Rows, Productiveness, and 
Deleterious Characters in Corn. Curtis H. Kyle and Hugo F. 
Stoneberg_ 83 O 
Bean Varietal Tests for Disease Resistance. R. D. Rands and Wilbur 
Brotherton, Jr. (3 plates)_ 101 
Effect of Dehydration upon the Bacterial Flora of Eggs. George G. 
De Bord_ 155 
The Effect of Low Temperatures on Bruchus obtectus Say, an Insect Af¬ 
fecting Seed. Walter Carter (6 text figures)_ 165 
The Influence of Irrigation Water and Manure on the Composition of 
the Corn Kernel. J. E. Greaves and D. H. Nelson_ 183 
Cleaning Milking Machines. L. H. Burgwald_ 191 
Laboratory Tests on Effect of Heat on Seeds of Noble and Silver Fir, 
Western White Pine, and Douglas Fir. J. V. Hofmann_ 197 
Vitamin A in Beef, Pork, and Lamb. Ralph Hoagland and George G. 
Snider (1 plate; 23 text figures)_ 201 
The Relationship Between the Weight of Eggs and the Weight of Chicks 
According to Sex. M. A. Jull and J. P. Quinn_ 223 
Tests of Deep-Well Turbine Pumps. F. L. Bixby (16 text figures)_ 227 
Colloidal Silica and the Efficiency of Phosphates. P. L. Gile and J. G. 
Smith (1 plate)_ 247 
Best Time for Sowing Silver Fir in the Nursery. J. V. Hofmann (3 text 
figures)_ 261 
Girdling as a Means of Removing Undesirable Tree Species in the Western 
White Pine Type. Donald R. Brewster and Julius A. Larsen_ 267 
Comparative Susceptibility of Onion Varieties and of Species of Allium 
to Urocystis cepulae. P. J. Anderson_ 275 
The Nitrogen Constituents of Celery Plants in Health and Disease. 
G. H. Coons and L. J. Klotz_ 287 
Steam and Chemical Soil Disinfection with Special Reference to Potato 
Wart. N. Rex Hunt, F. G. O’Donnell, and Rush P. Marshall (2 
plates; 3 text figures)_ 301 
The Nutritive Value of Wheat: I.—Effect of Variation of Sodium in a 
Wheat Ration. George A. Olson and J. L. St. John (6 text figures) __ 365 
An Approximate Method of Calculating Coefficients of Inbreeding and 
Relationship from Livestock Pedigrees. Sewall Wright and Hugh 
C. McPhee_ 377 
Further Studies on Isoelectric Points for Plant Tissue. William J. 
Robbins and Irl T. Scott (3 text figures)- 385 
The Minimum Temperature for Growth of the Date Palm and the Absence 
of a Resting Period. Silas C. Mason (4 text figures)- 401 
Partial Thermostasy of the Growth Center of the Date Palm. Silas C. 
Mason (5 plates; 6 text figures)_ 415 
The Inhibitive Effect of Direct Sunlight on the Growth of the Date Palm. 
Silas C. Mason (3 text figures)_ 455 
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