688 Journal of Agricultural Research voi.vi.No.is 



Before entering a discussion of the life cycles of other bacteria, the 

 serial numbers for the four subcycles of B. azotobacter may be given, de- 

 termined, so far as possible, in accordance with the methods recommended 

 by the Society of American Bacteriologists. The behavior in the presence 

 of the different carbonaceous substances, however, had to be tested in 

 our mineral solution with nitrate to which 0.5 per cent of the different 

 sugars, etc., was added, the highly concentrated peptone solution not 

 being suitable for this organism. That the appearance of the colonies, 

 as well as the other cultural characteristics, differs accordingly, goes with- 

 out sajdng; these details will also be given later. The serial numbers 

 resulting from our tests are as follows : 



Type A. — 221.2322813. Type E. — 222.2222524. 



Type L. — 121.3332033. Type F. — 122.4442034. 



THE LIFE CYCLES OF OTHER BACTERIA 



The following 18 cultures were selected as representatives of practically 

 all groups of bacteria. 



No. 31. B. subtilis, isolated from evaporated milk. 



No. 32. B. lactis niger, Gorini's original culture from Krai's Museum. 



No. ^^. Tyrothrix tenuis, Duclaux' original culture from Krai's Museum. 



No. 34. B. danicus, isolated from soil. 



No. 35. Bad. pneumoniae, isolated from soil. 



No. 36. Bad. radiobacter, isolated from soil. 



No. 38. Bad. denitrificans agile, Ampola's original culture from Krai's Museum. 



No. 39. Bad. radicicola, isolated from vetch. 



No. 40. Bad. fluorescens, isolated from milk. 



No. 41. A yellow bacillus (not determined) isolated from soil. 



No. 42. Planosarcina ureae, Beijerinck 's original culture from Krai's Museum. 



No. 43. Sarcinaflava, isolated from milk. 



No. 44. Micrococcus candicans, isolated from chernozem. 



No. 45. Micrococcus candicans, isolated from evaporated milk. 



No. 46. Salt-water spirillum isolated from Great Salt Lake, Utah. 



No. 47. Salt-water spirillum isolated from sea water. 



No. 48. Streptococcus lactis, kindly furnished by Dr. L. A. Rogers, Bureau of 



Animal Industry. 



No. 49. Bad. bulgaricum, kindly furnished by Dr. L. A. Rogers. 



Before being tested, these cultures had been grown on the following 

 substrates : 



Beef agar: No. 31-36, 38, 40, 41, 43~45- 



Beef agar plus 3 per cent of sodium chlorid: No. 46, 47. 



Beef agar plus 0.5 per cent of urea: No. 42. 



Saccharose agar: No. 39. 



Milk: No. 48, 49. 



After having been examined as to their purity on agar plates, they were 

 cultivated on the different agars and in suitable solutions. Beef, salt, 

 and urea agars were used as before. In the case of B. radicicola (No. 39), 



