496 SUMMARY OF CURRENT RESEARCHES RELATING TO 



genus has teleutospores of a similar structure to those of Coleosporium, 

 but arranged in two superposed layers ; in the latter the teleutospores 

 are also composed of four cells, but in two pairs lying side by side ; they 

 are abstrioted in long straight rows. 



Effect of Chemical Media on the Growth of the Dematieae.* — 

 M. L. Planchon recounts the results of a large number of experiments 

 on the growth of about 20 species of this class of fungi in a number of 

 different nutrient fluids and chemical solutions. The terms fumagoid, 

 alternarioid, macrosporoid, cladosporoid, &c, are used to denote the dif- 

 ferent growth-forms in the various species. Among the more interest- 

 ing results are the following. The solid nutritive medium most favour- 

 able for all the cultures (typical medium) is potato acidified by lying 

 for a quarter of an hour in 1 per cent, sulphuric acid. The Dematiese 

 are much more subject to morphological diversity dependent on the 

 chemical composition of the medium, than are the Mucedineaa. These 

 modifications affect the vegetative much more than the reproductive 

 organs, and are a mode of defence against desiccation and against the 

 injurious effects of the medium. The most common forms of such modi- 

 fications are the thickening, encysting, or gelification of the cell-wall, 

 or the change in the form of the filament itself, the production of chlamy- 

 dospores, or of isolated cells capable of germinating (oidia), or of 

 toruloid forms in which the mycelial filament has entirely disappeared. 

 All kinds of transitional forms between the extremes occur. 



Dematium pullulans and Cladosjporium herbarum must be regarded as 

 distinct species. Two new species of Alternaria are described, A. varians 

 and A. poh/morpha. 



Nodule Organism of the Leguminosse.t — Mr. E. Greig Smith 

 gives a resume of the various views taken by different observers with 

 regard to the nature of the organism found in the root-tubers of the 

 Leguminosse, and then gives his own conclusions, derived chiefly from 

 an examination of the lupin. He obtained the organism in pure cultures 

 as an oval vacuolated yeast with a faculty of budding ; this property, 

 together with the presence of a more or less persistent mucilaginous 

 capsule, causes the organism to assume a variety of shapes. The more 

 vigorous forms are motile, the motility being due to a single terminal 

 tufted flagellum. The author adopts Frank's name for the organism, 

 viz. JRhizobium leguminosarum. It is usually accompanied by Bacillus 

 megaterium, and often by other bacteria. 



Jorgensen's Micro-organisms and Fermentation, j — The third 

 edition of Dr. A. Jorgensen's treatise on Micro-organisms and Fermen- 

 tation has recently appeared in an admirable translation by Mr. A. K. 

 Miller and Mr. A. E. Lennbolm. The general scope of the work is to 

 give an account of the morphology and biology of the microbes of fer- 

 mentation, and in this respect it occupies a prominent position among the 

 books dealing with these subjects. As might be anticipated, there is 

 much praise and appreciation of Hansen's work, methods, and results, 

 which are described with commendable lucidity. The volume appeals 



* Ann. Sci. Nat. (Bot.), xi. (1900) pp. 1-248 (4 pis. and 63 figs.). 



t Proc. Linnean Soc. N.S. Wales, xxiv. 1899 (19(10) pp. 653-73 (2 pis.). 



X London, Macmillan & Co., Ld., 1900, xiii. and 318 pp., 83 figs. 



