CONTENTS 



Effect of Time of Digestion on the Hydrolysis of Casein in the Page 



Presence of Starch. J. S. McHargue i 



Behavior of Sweet Potatoes in the Ground. Heinrich Has- 



SELBRING 9 



Studies in Soil Reaction as Indicated by the Hydrogen Electrode. 



J. K. Plummer 19 



Pure Cultures of Wood-Rotting Fungi on Artificial Media. W. H. 



Long and R. M. Harsch 33 



Gossypol, the Toxic Substance in Cottonseed. W. A. Withers 



and Frank E. Carruth 83 



Fruit-Fly Parasitism in Hawaii During 191 6. C. E. PembERTOn 



and H. F. Willard .• 103 



Irrigation Experiments on Apple-Spot Diseases. Charles 



Brooks and D. F. Fisher 109 



Relation of Carbon Dioxid to Soil Reaction as Measured by the 



Hydrogen Electrode. D. R. Hoagland and L. T. Sharp. . . . 139 

 A Study of the Plow Bottom and Its Action Upon the Furrow 



SHce. E. A. White i49 



Influence of Nitrates on Nitrogen-Assimilating Bacteria. T. L. 



Hills 183 



New-Place Effect in Maize. G. N. Collins 231 



Relation of the Variability of Yields of Fruit Trees to the Accu- 

 racy of Field Trials. L. D. Batchelor and H. S. Reed 245 



Interrelations of Fruit-Fly Parasites in Hawaii. C. E. Pember- 



TON and H. F. Willard 285 



Water Extractions of Soils as Criteria of their Crop-Producing 



Power. John S. Burd 297 



Effect of Season and Crop Growth in Modifying the Soil Extract. 



Guy R. Stewart 311 



The Freezing-Point Method as an Index of Variations in the Soil 



Solution Due to Season and Crop Growth. D. R. Hoagland. . 369 

 Efficacy of Some Anthelmintics. Maurice C. Hall and Win- 



throp D. Foster 397 



Tobacco Wildfire. Frederick A. Wolf and A. C. Foster .... 449 

 Gipsy-Moth Larvae as Agents in the Dissemination of the White- 

 Pine Blister-Rust. G. Flippo Gravatt and G. B. Posey 459 



Influence of Carbonates of Magnesium and Calcium on Bacteria of 

 CC Certain Wisconsin Soils. H. L. Fulmer 463 



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