FIELD CR0P8. 1 25 



generic classification the system of Migula, based upon the character of the flagella, 

 i- recommended. The division of genera into groups is based on leading characters, 

 such as spore formation, relation to oxygen, liquefaction of gelatin, fermentation of 

 lactose, dextrose, and saccharose, reductit f nitrates, and chromogenesis. 



The effect of freezing- on bacteria, E. I'. Smith and l>. B. Swingle (Abs. in 

 Science, n. ser., :i (1905), No. 535, />/>. $81 $88). The results "I" experiments made 

 in freezing a number <>f differenl species of bacteria and other plant and animal 

 pathogenic forms are given. Some of the freezings were made in liquid air with 

 usually one-half hour exposure, while the others were nun It- in salt and ice, with an 

 exposure of 2 limns. After freezing, thawings were made in tap water, and inocula- 

 tions made from the cultures. These were sown mi plates and the colonies counted 

 alter development. . 



The authors found that the effect of very low temperatures in destroying bacteria 

 has been greatly overestimated. The results wen- as destructive with sail and 

 pounded ice a- with liquid air. The critical period of bacteria seems to be about 

 n C, and if an organism can pass this point in safety il is believed thai it would not 



be injure. I l.y any amount of cold that could he applied. In every culture some 



individuals were found that were unharmed when subjected to the temperature of 

 liquid air I I'.M) C.)i although the number was a very small proportion of the 

 w hole. Repealed f reezings an. 1 thawings gradually reduced the number of organisms 

 present, although l<» freezings and thawings in the course of s hours did not kill all 

 the individuals of the cabbage black rot organism I Pseudomonas campeslris). 



So far as any genera] inference can be drawn from the experiments, the authors 

 conclude that bacteria behave very much like the higher plants and animals in 

 respect to injury by freezing. 



The metabolism of chromogenic bacteria, M. X. Sullivan (Abs. in Science, >>. 

 her., :i (1905), No. 5S5,pp. '(89,490). — Synthetic culture media are said to he the best 

 for the biochemical study of bacteria. 



Some bacteria show little power to grow upon synthetic media, hut it is believed 

 probable that the power to grow on such media can he developed and that the 

 me. limn may he accommodated to the organism or the organism to the medium. 

 Manx- bacteria grow readily on synthetic culture media with or without pigment 

 formation. Whether producing pigment or not these chromogenic bacteria give the 

 same metabolic products, as far as they have been analyzed. 



The metabolic products so far investigated are various acids, ammonia, alcohol, 

 benzol derivatives, and albuminous bodies. The metabolic products of a number of 



specie- are listed. 



A review of the Bacillus subtilis group of bacteria, F. I>. Chester i Centbl. 

 lUtkl. [>ir ], .'. Abt., 13 I 1904), No. .'I. pp 137-752).— The author gives a review of 

 studies on the Bacillus subtilis group of bacteria, which is limited to those species of 

 bacillus which produce spores, liquefy gelatin, and grow under aerobic conditions. 

 Thf morphology of the bacteria i> described, notes being given <>n the measurement, 

 spore formation, germination, vegetative stage, etc.. after which the cultural features, 

 chemical functions, and classification of a number of species are discussed at length. 



FIELD CROPS. 



Field experiments with farm crops, \Y. Saunders, .1. II. Grisdale, W. T. 

 Mac. r\, F. T. Sm tt. J. Fletcher, C. E. Sai nders, R. Robertson, S. A. Bedford, 

 A. Mack ay, and T. A. Sharpe (Canada Expl. Farms Rpts. 1904, pp. 19-87,78-108, 

 *U8-181, I.:-'., 136, 182-191, 955, U6, 259-281, 816-839, 871^889, 111-4S5, 45 



'I'jui. I). — The result- of experimental work with field crops at the Canada experi- 

 niental farms in 1904 are reported. The work was carried on in continuation of 

 experiments generally in progress for a >eries of years | 1'.. S. R., 16, p. 246). 



