1916] AGRICULTURAL BOTANY. 729 



life cycle of each species of bacteria studied was found to embrace several sub- 

 cycles showing wide morphological and physiological differences. 



Studies of Bacillus radicicola, J, C. Temple (Georgia Sta. Bui. 120 (1916), 

 pp. 67-80, figs. 6).— Studies are reported of the use of cultures for inoculating 

 legumes and of the employment of sterilized soil as a medium for growing 

 B. radicicola. 



A number of commertrial cultures were tested on different media, including 

 soil, and the number of viable bacteria in the sample was determined. The 

 results given in detail in a table show a relatively high bacterial content of the 

 cultures grown in soil. To secure data on the life of B. radicicola on dry seed 

 Canada field peas were inoculated and stored in a loosely stoppered bottle after 

 drying. Seeds from this lot were planted in bottles of sterilized sand at inter- 

 vals of thirty days. Nodules were formed on all plantings up to the fifth month. 



The purpose of the study of sterilized soil as a medium for growing B. radi- 

 cicola was to determine whether this organism grows more vigorously in soil 

 than in the usual culture solutions, and how the longevity of the two kinds of 

 cultures compares. 



Two sets of samples were started May 22, 1912, one inoculated with B. radi- 

 cicola from soy bean and the other with the similar organism from crimson 

 clover. Counts of the soy bean culture made on different dates showed that 

 from the second week on the number of bacteria in the soil greatly exceeded the 

 number in solution and in the soil the increase continued as long as the tenth 

 week, while in the solution the maximum was reached in two weeks when the 

 number of bacteria was only about one-tenth that in the soil sample. The 

 crimson clover culture grew less vigorously but the soil appeared to be much 

 more favorable for its development than the culture solution. The soil culture 

 used March 17, 1916, to inoculate crimson clover in tubes was able to produce 

 numerous nodules. Similar results were secured with alfalfa cultures. In each 

 experiment the soil cultures showed the greater longevity. 



An experiment was conducted also to determine what influence various sub- 

 stances used in the preparation of media have on the development of B. radi- 

 cicola in solutions and in soil. The results indicated that of the different sugars 

 used cane sugar and dextrose were very much superior to lactose, while levulose 

 was of no value. A repetition of the experiment also indicated that levulose 

 was entirely unsuited to this organism. The presence of ground alfalfa caused 

 rapid multiplication in solution and in soil, the larger number being in the soil. 



The evidence brought out by these experiments indicated that of the different 

 media compared sterilized soil, with the addition of a small amount of legumi- 

 nous material, was the best medium for the propagation of B. radicicola. 



The influence of energy material upon the relation of soil inicro-organisms 

 to soluble plant food, C. J. T. Dokyland (North Dakota Sta. Bui. 116 (1916), 

 pp. S19-401, figs. 2). — Following a review and discussion of previous work, re- 

 sults are given of an extended study of six common ammonifying organism* to 

 test their ability to consume ammonia in the presence of dextrose as a source 

 of energy. The organisms used were Bacterium mycoides, B. subtilis, B. mega- 

 therium, B. proteus, B. vulgatus, and Sarcina lutea. In the experiments the 

 author investigated the ability of these organisms to grow and produce ammonia 

 from casein in both the presence and the absence of dextrose; the effect of 

 increasing quantities of dextrose upon the number of bacteria and the ammonia 

 production in the casein solution ; the competitive action between the ammonify- 

 lEg bacteria and maize seedlings when grown in the presence of dextrose ; the 

 effect of adding ammonium sulphate, potassium nitrate, casein, or manure on 

 the growth of oats in quartz sand to which dextrose had been added ; the 



