AGBICTILTURAL BOTANY. 529 



AGRICULTURAL BOTANY. 



A text-book of general bacteriology, W. D. Frost and E. F. McCampbell 

 {New York., Id 10, pp. XVII+3.'fO, figs. 61).— This is a brief but comprebeusive 

 text on general bacteriology designed for college classes. It includes a study 

 of tbe morpbology of bacteria, metbods used in tbeir study, tbeir taxonomy 

 and general pbysiology, tbe biology of specialized groups sucb as tbe proto- 

 trophic, cbromogenic, pbotogenic, zymogenic, saprogenic, sapropbilic, patbo- 

 genlc bacteria of animals and plants, and tbe distribution of bacteria, includ- 

 ing bacteria of tbe soil, air, water, sewage, milk, and of tbe buman body. 



Beview of agricultural bacteriology, E. Kayser {BuI. Mens. Off. Renseig. 

 Agr. [Paris], 9 {1910), No. 10, pp. 1150-1160). — A review is given of recent 

 publications by various investigators on bumiflcation, soil fatigue, nitrifica- 

 tion, denitrification, purification of sewage waters, nitrogen fixation, and tbe 

 inoculation of seeds witb cultures of tubercle bacteria. 



Bacteria in frozen soil, H. J. Conn {Centbl. Bakt. [etc.^, 2. AM., 28 {1910), 

 No. 16-19, pp. 422-Ji34, dgim. 2). — Tbe results are given of tbe bacterial count 

 from samples of soil taken to a deptb of from 15 to 18 cm. from April, 1909, to 

 April, 1910, at Itbaca, N. Y. Very dilute soil suspensions from these samples 

 were plated on a 12 per cent gelatin medium and incubated at from 19 to 20° 

 C. for 7 days before tbe counts were made. 



Quantitative determinations by means of tbe plate method showed the pres- 

 ence of large numbers of bacteria during tbe winter in the soil samples. 

 When tbe soil was completely frozen there seemed to be a rapid multiplication 

 in the numbers of bacteria, gi-eater than any found during tbe summer or fall. 

 In general, tbe number seems to vary with the moisture content of tbe soil, 

 but the rapid multiplication during the winter was an exception to this rule. 

 There were indications tbat the bacterial flora of tbe soil consist of two 

 groups, one flourishing in tbe winter, and the other in the summer. 



Variability in Bacillus prodigiosus, M. W. Beijerinck {K. Akad. Wetensch. 

 Amsterdam, VersL Wis en Natuurk. Afdeel., 18 {1909-10), pt. 2, pp. 596-605; 

 K. Akad. Wetemch. Amster-d<im, Proc. Sect. Sci., 12 {1909-10), pt 2, i)p. 6^0- 

 6/t9). — The author gives the metbods used in obtaining some 14 variants of B. 

 prodigiosus and tbeir salient characters. 



It is claimed tbat B. prodigiosus produces both gain and loss variants, all 

 obtained witb certainty by actual experiments, in which the same culture will 

 contain the stock-form unchanged, as well as the variants. By rapidly re- 

 peated reinoculations and by other metbods the normal form and variants may 

 be kept constant apparently for an unlimited length of time. These variants 

 differ from each other and from their stock-forms in the same way as closely 

 related natural species or varieties do from each other. 



The bacterial flora as a factor in the unproductiveness of soils, A. Dach- 

 NowsKi {Ohio Nat., 10 {1910), No. 6, pp. 137-lJi5, figs. 2).— In a contribution 

 from the botanical laboratory of tbe Ohio State University the author gives 

 tbe results of experiments on the toxin-producing power of pure cultures of 

 bacteria isolated from the bog water from the uppermost layer (1 ft. deep) of 

 soil from Cranberry Island at Buckeye Lake, Ohio. 



The physiological tests were made in half -liter Mason jars containing 500 

 cc. of inoculated solutions obtained by inoculating sterilized solutions of bog 

 water and peat with pure cultures of tbe isolated bog bacteria, and with a 

 mixture of bacteria found in 1 cc. of fresh bog water. Check experiments were 

 also carried on witb sterilized uninoculated solutions and witb normal untreated 

 bog water. All flasks were incubated from 2 to 6 weeks prior to tbe physio- 



