Abstracts of Doctoral Theses pages 1-106

The Efficacy of the Ultra-violet Light Sources in Killing Bacteria Suspended in Air. B.A. Whisler pages 215-232

Anaerobic Decomposition of and Gastifacation of Cornstalks by Thermophiles. G.H. Nelson, R.P. Straka, and Max Levine pages 233-252

The Dissimilation of Phosphoglyeric Acid and Hexosediphosphate by Aerobacter indologenes. R.W. Stone, M.N. Mickelson, and C.H. Werkman pages 253-260

The General Differential Operator. Fred Robertson pages 261-266

Insects as Vectors of Yellow Dwarf, a Virus Disease of Onions. H..D. Tate pages 267-294

Stresses in an Orthotropic Elastic Layer. R.H. Tripp and D. L. Holl pages 295-304

Effect of pH on the Toxicity of Nicotine Injected into the Cockroach Periplaneta americana (L.). Charles H. Richardson and L.O. Ellisor pages 305-316

Nature of Eimeria nieschulzi-growth-promoting Potency of Feeding Stuffs. I. Positive of Gray Shorts. Elery R. Becker pages 317-322

Some New and Heretofore Unrecorded Nabidae (Hemiptera). Halbert M. Harris pages 323-332

Circulation of Hemolymph in the Wings of the Cockroach, Blattella germanica L. I. In Normal Wings. Stewart Clare and Oscar E. Tauber pages 107-128

Fungi Associated with Tree Cankers in Iowa. II. Diaporthe, Apioporthe, Cryptodiaporthe, Pseudovalsa and Their Related Conidial Forms. Joseph C. Gilman and G.L. McNew pages 129-154

Preliminary Studies on the Comparative Value of Some Sprays and Dusts in Potato Insect Control. H.C. Manis and Ila Leffert pages 155-162

Examination of Ice Cream with the Burri Smear Culture Technic. H.F. Long and B.W. Hammer pages 163-178

Preparation of an Active Juice from Bacteria. W.P. Wiggert, M. Silverman, M.F. Utter, and C.H. Werkman pages 179-186

Description of a Dexto-Lactic Acid Forming organism of the Genus Bacillus. A.A. Anderson and C.H. Werkman pages 187-194

Effect of Low Temperatures on the Intensity of Fluorescense. J.E. Dinger and William Kunerth pages 195-198

A Supplement to the Catalogue of Iowa Plants in the Iowa State College Herbarium. Ada Hayden pages 199-214

A Functional Method for the Solution of Thin Plate Problems Applied to a Square, Clamped Plate with a Central Point Load. C.J. Thorne and J.V. Atanasoff pages 333-344

Preliminary Studies on the Use of Dinitro-O-Cresol Dusts in Grasshopper Control. G.C. Decker and C.J. Drake pages 345-352

Some Reactions of Grasshoppers to Castor Bean Plants. Louis A. Spain pages 353-358

The Dissimilation of Levulose by Heterfermentative Lactic Acid Bacteria. M.E. Nelson and C.H. Werkman pages 359-366

Nutritive Requirements of the Heterofermentative Lactic Acid Bacteria. H.G Wood, Charles Geiger, and C.H. Werkman pages 367-378

The Quantity of Pericarp in Several Hybrid and Inbred Strains of Sweet Corn. W.G. Gaessler, R.M. Nixon, and E.S. haber pages 379-384

The Response of the Plum Grown Under Hillculture Conditions to Modifications in Cultural Treatment. J.M. Aikman and H.E. Brewer pages 385-392

Motility of the Excised Fore-gut of Periplaneta americana (Orthoptera) in Various Salt Solutions. J.T. Griffiths Jr. and Oscar E. Tauber pages 393-404

Effect of Ether on the Toxicity of Certain Fumigants to the Confused Flour Beetle, Tribolium confusum Duval. Harold Gunderson pages 405-418

Index to Volume XIV pages 419- 424