126 REPORT OF COMMITTEE 



modification e.g., reducing the amount of peptone in the me- 

 dium, for organisms that grow so rapidly as to cover the entire 

 surface of the plate in seven days, thus leaving no room for a 

 clear zone outside. 



The growp-numher is a brief means of recording the salient 

 features of the organism. It is primarily a summary of the 

 physiological characteristics just discussed. As each of the 

 determinations is made, the proper figure for that place ia the 

 group number is to be checked or underscored. After com- 

 pleting the determinations, the entire group number is to be 

 written in at the place left for it on the chart. The genus symbol 

 should precede the group number. The present group number, 

 adopted by the Society in 1907, is intended for use with the 

 generic names of Migula. As Migula's genera are not in such 

 general use today as they were ten years ago, a revision of the 

 group number on some other basis will be necessary in the near 

 future. 



Brief characterization. On the right hand margin of page one 

 of the chart is a place for recording by a + or — sign other 

 important characteristics of the organism (primarily cultural) 

 not included in the group number. This margin together with 

 the group number constitute a brief characterization of the 

 organism, — a summary of the tests outlined above. 



REFERENCES 



Allen, P. W. 1918 A simple method for the classification of bacteria as to 

 diastase production. J. Bact. 3, 15-18. 



American Public Health Association. 1916 Standard methods for the exami- 

 nation of water and sewage. 



American Public Health Association 1917 Standard methods of bacteriological 

 analysis of milk. Am. J. Pub. Health, 6, 1315-1325. 



Clark, W. M. and Lubs, H. A. 1917 a The colorimetric determination of hy- 

 drogen-ion concentration. J. Bact. 2, 1-34, 109-136, 191-236. 



Clark, W. M. and Lubs, H. A. 1917 b A substitute for litmus for use in milk 

 cultures. J. Agric. Research, 10, 105-111. 



RoTHBERG, W. 1917 Observations on some methods for the study of gelatine 

 liquefaction. Read before Soc. Amer. Bacteriologists, December, 

 1917. 



