IV CONTENTS 



No. 4, July, 1921 



Spiral Bodies in Bacterial Cultures. Laura Florence 371 



The Cause of Eyes and Characteristic Flavor in Emmental or Swiss Cheese. 



James M . Sherman 379 



A New Modification and Application of the Gram Stain. G. J. Hucker... . 395 

 Color Standards for the Colorimetric Measurement of H-Ion Concentration. 



Louis J. Gillespie 399 



The Effect of Pepton upon the Production of Tetanus Toxin. Harriet 



Leslie Wilcox 407 



On the Growth and the Proteolytic Enzymes of Certain Anaerobes. K. G. 



Dernby and J. Blanc 419 



No. 5, September, 1921 



The Mannitol-Producing Organisms in Silage. G. P. Plaisance and B. W. 



Hammer 431 



Principles Concerning the Isolation of Anaerobes. Studies in Pathogenic 



Anaerobes IL Hilda Hempl Heller 445 



Indol Production by Bacteria. John F. Norton and Mary V. Sawyer 471 



On Nitrification. IV. The Carbon and Nitrogen Relations of the Nitrite 



Ferment. Augusto Bonazzi 479 



Toxins of Bact. Dysenteriae, Group III. Th. Thj0tta 501 



No. 6, November, 1921 



Salt Effects in Bacterial Growth. I. Preliminary Paper. George E. Holm 

 and James M . Sherman 511 



Suggestions concerning a Rational Basis for the Classification of the Anaero- 

 bic Bacteria Studies in Pathogenic Anaerobes IV. Hilda Hempl 

 Heller 521 



Hydrogen Ions, Titration and the Buffer Index of Bacteriological Media. 



J. Howard Brown 555 



On Decreasing the Exposure Necessary for the Gelatin Determination. 



J. E. Rush and G. A. Palmer 571 



Chart of the Families and Genera of the Bacteria. Harold Macy 575 



