498 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The anatomy of the group is first of all dealt with, including the tricho- 

 mata, sheaths, and branching, then the development and reproduction, 

 followed by biological remarks and method of examination ; finally a 

 systematic description and bibliography. The author holds that the 

 Cyanophyceee possess true chromatophores, though differing considerably 

 from those of other algae, and exhibiting a lower degree of differentiation. 

 He has failed to find in them a true nucleus ; the highly refractive 

 granules are either evenly distributed through the cell, or are confined 

 to the neighbourhood of the cell-wall and arranged in rows. Their 

 chemical constitution is unknown ; they do not consist of starch. 



/3. Schizomycetes. 



Importance of Bacteria to the Development of Plants.* — Herr J. 

 Stoklasa has performed contrast experiments on Brassica oleracea grown 

 in enclosed vessels containing sterilised loamy sand. In one case the 

 sand remained sterilised ; in the other it was inoculated with a mixture 

 of the following soil bacteria: — Bacillus mycoides, B. fluorescens lique- 

 f a dens, B. proteus vulgaris, B. subtilis, B. butyricus, B. mepaterium, B. 

 urese, B. mesentericus vulyalus, and B. coli communis. To the inoculated 

 vessels were added 5 grm. of dextrose. In all cases the total weight of 

 the dried plant, and the total weight of seed, were greater in the inocu- 

 lated than in the sterile vessels. Stoklasa concludes that in the absence 

 of micro-organisms vegetation is abnormal, and that incompletely de- 

 veloped seed is produced. 



Diagnosis of Bacteria.']'— Sig. L. Macchiati considers that the aureola 

 which surrounds bacteria mounted in balsam, and which is visible at 

 some stage of their development, is to be regarded as a specific indication. 

 The appearance results from a solidification of the gelatinous outer layers 

 of the investing membrane. The author also attaches great importance 

 to photograms of impressions of colonies in the determination of bacterial 

 species. The cultures should be made on agar plates, and should be 

 young. Under such conditions the photographic appearances are typical 

 and decisive. 



Acquired Movement and the Loss of Flagella in Bacteria.*— Herr 

 F. Zierler made a careful examination of Bacillus implexus Zimmermann 

 and Bacillus subtilis Cohn, and found that, besides some slight cultural 

 differences, B. implexus was motile at all ages and on all media. 



The conclusion drawn from this is that B. implexus, which was origi- 

 nally devoid of motion, had acquired motility in the course of time. 

 This view is supported by Dr. K. B. Lehmann, who remarks that it is 

 the first genuine instance of the acquisition of movement yet recorded. 



The converse, namely, the loss of flagella in Micrococcus agilis and 

 M. citrcus agilis, after prolonged cultivation, has been already reported. 



Influence of the Temperature of Liquid Air on Bacteria. — Dr. A. 

 Macfadyen and Mr. S. Rowland, § who had previously shown tbat no 



* Zeit Zuckerind. Bohm., xxiv. (1000) pp. 222-7. See Juurn. Chem. Soc, 1900, 

 Abstr., ii. p. 360. 



t Nuov. Giorn. Bot. Ital., vi. 1899, pp*. 384-410 (2 pis. and 12 figs.). 



t Arch. f. Hygiene, xxxiv. (1899) pp. 192 and 198. See Centralbl. Bakt. u. Par., 

 2 ,e Abt., vi. (1900) pp. 297-8. 



§ Proe. Boy. Soc, lxvi. (1900) pp. 339-40* Cf. this Journal, ante, p. 371. 



