Apr. i-Sept. is. 1921 
Contents 
v 
Page 
Effect of the Length of Day on Seedlings of Alfalfa Varieties and 
the Possibility of Utilizing This as a Practical Means of Identi¬ 
fication. R. A. Oakley and H. L- WestoveR (h plates)- 599 
Studies in the Physiology of Parasitism with Special Reference 
to the Secretion of Pectinase by Rliizopus tritici. L. L. Harter 
and J. L. .. 609 
Respiration and Carbohydrate Changes Produced in Sweet 
Potatoes by Rliizopus tritici. J. L. Weimer and L. L. HarTER . 62 7 
Wound-Cork Formation in the Sweet Potato. J. L. Weimer and 
L. L. Harter. ^37 
Two Sclerotium Diseases of Rice. W. II. Tisdale (5 plates).... 649 
A Biological Study of the Red Date-Palm Scale, Phoenicoeoccus 
marlatti. Arthur D. Borden (4 plates).. 659 
Red Date-Palm Scale, Phoenicoeoccus marlatti: A Technical 
Description. Harold Morrison (i text figure, 4 plates).... 669 
Some Observations Regarding Eosinophiles. Lewis H. Wright. 677 
A Souring of Beef Caused by Bacillus megatherium. Hubert 
BunyEA (2 text figures). 689 
A Fungus Disease Suppressing Expression of Awns in a Wheat- 
Spelt Hybrid. Lloyd E. Thatcher (i plate)... 699 
Effect of Ammonium Sulphate upon Plants in Nutrient Solutions 
Supplied with Ferric Phosphate and Ferrous Sulphate as 
Sources of Iron. Linus H. Jones and John W. SiiivE (9 text 
figures; 1 plate). 7 QI 
Dispersion of Flies by Flight. F. C. Bishopp and E. W. LaakE 
(3 text figures). 7 2 9 
Bacteriological and Chemical Studies of Different Kinds of 
Silage. Charles A. Hunter (6 text figures).•.. • • 767 
Sandy Crystals in Ice Cream: Their Separation and Identification. 
Harper F. ZollER and Owen E. Williams (2 plates). 791 
Solenopotes capillatus, a Sucking Louse of Cattle Not Heretofore 
Known in the United States. F. C. Bishopp (6 text figures). . 797 
Rate of Culm Formation in Bromus inermis. L. R. Waldron (2 
text figures). 8o 3 
Reliability of the Nail Test for Predicting the Chemical Com¬ 
position of Green Sweetcorn. Charles O. Appleman (i text 
figure)... 81 7 
Transmission of Some Wilt Diseases in Seed Potatoes. M. B. 
McKay (8 text figures; 3 plates). 821 
Correlation and Growth in the Branches of Young Pear Trees. 
H. S. REED (7 text figures; 1 plate). 849 
Index. 8 77 
