226 EXPERIMENT STATION RECORD. 



Contributions to the cytology of the bacteria, C. C. Dobell {Quart. Jour. 

 Micros. Sci. [London], n. ser., 56 (1911), No. 223, pp. 395-506, pis. 4, fi9- !)■— 

 After a general review of the literature on the cytology of the bacteria, in 

 which the views of each investigator are briefly stated, together with the 

 technique used, the author describes his own methods and gives the sources 

 of his material, descriptions of the forms investigated, and the cytolo^ical 

 results obtained from the studies. 



The conclusion is reached that all bacteria which have been adequately in- 

 vestigated are, like all other protista, nucleate cells. The form of the nu- 

 cleus is variable in different bacteria and in different periods of the life cycle 

 of the same species, and may consist of a discreet system of granules (chro- 

 midla) of one or more relatively large aggregate masses of nuclear substance, 

 of a system of irregularly branched or bent short strands, rods, or netwoks, 

 or of a filament of varying contiguration, aud probably also may exist in the 

 vesicular form characteristic of the nuclei of many plants, animals, and 

 protists. 



Nuclei equivalents and nuclei of Azotobacter chroococcum and its spore 

 formation, E. Mencl (Arch. Protistenk., 22 {1911), No. 1, pp. 1-18, pi. 1).— 

 After a general description of the material and methods used in his investiga- 

 tions, the author gives the results of a cytological study on the internal struc- 

 ture and spore formation of Azotobacter, in which a simple form of mitosis, 

 nuclei or their equivalents, sporulation, and involution forms were observed 

 and described. 



On the mineral needs of Azotobacter, H. Kaserer {Ztschr. Landiv. Yer- 

 snchsio. Ostern, 14 {1911), No. 2, pp. 97-123).— This is a more extended dis- 

 cussion of investigations by the author on this subject, including details as to 

 methods used and data obtained in arriving at the results which were sum- 

 marized in a previous paper (E. S. R., 24, p. 29). 



Viability of Pseudomonas radicicola on ash-maltose ag"ar, S. F. Edwards 

 {Abs. in Science, n. ser., 33 {1911), No. 8.'/.9, pp. 5 ',3, 54-'/).— During the latter 

 part of 1906 cultures of P. radicicola were isolated from the nodules of 19 

 hosts on ash-maltose-agar and then transferred to the same medium in Freu- 

 denreich flasks which were kept in a darkened cupboard at laboratory room 

 temperature. In the autumn of 1910 plates were made from these old cultures 

 with the result that in 15 of them the organism was still living. Pot tests 

 in sterile sand, using seeds of alfalfa, red clover, peas, and beans were started, 

 but only the peas were sufficiently developed at the time of writing to examine. 

 Of 6 noninoculated control plants, 3 showed no nodules, and 3 showed 1, 10, 

 and 12 nodules, respectively, while the 6 inoculated plants showed 18, 33, 20, 

 25, 64, and 25 nodules, respectively. The work thus far shows that P. radici- 

 cola retains its virility as well as its vitality after considerable periods of time 

 in stock cultures under laboratory conditions. 



The influence of quartz sand upon microbial cultures, O. Rahn (A 6s. in 

 Science, n. ser., 33 {1911), No. SJi9, p. SJt-'t)- — The object of this investigation 

 was to study the influence of soils upon micro-organisms. The decomposition 

 of liquid media was compared with that of the same liquid absorbed in quartz 

 sand, and great differences were found. Aerobic processes were greatly in- 

 creased and anaerobic processes much decreased when the liquid was mixed in 

 sand in such proportions as to allow abundant aeration, but both processes were 

 favored when just enough liquid was added to the sand to keep it entirely 

 submerged. 



Biochemical factors in the soil, M. X. Sullivan (Abs. in Science, n. ser., 

 33 {1911), No. 8-!i9, p. 5)3). — Attention is called to the fact that the soil is not 

 an inert reservoir for plant food, but is the seat of physical, chemical, and 



