ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



393 



Schizophyta. 

 Schizomycetes. 



Bacteroids of Bacillus radicicola.* — R. E. Buchanan finds that the 

 morphology of B. radicicola varies in artificial media according to the 

 nutrient employed ; sodium succinate causes the most luxuriant growth 

 and produces the greatest varieties of bacteroids ; glycerin especially 

 favours the development of bacteroids ; peptones inhibit growth and 

 production of bacteroids ; of fifteen carbo-hydrates tested all favoured 

 the development of bacteroids, and especially mannite. B. radicicola in 

 leguminous roots shows the same type of bacteroid as may be found in 

 suitable culture media. Probably the term B. radicicola includes a 

 closely related group of varieties differing from each other to some 

 degree in morphological characters. 



The author considers that the nodule organism resembles in its 

 morphology both yeasts and bacteria, and that the difference of this 

 form and those included under the terms "bacillus" and "pseudo- 

 monas " justify the use of the generic name " Rhizobium." 



Bacillus radicicola.f — 0. M. Ball finds from a number of observa- 

 tions on soils that B. radicicola can remain active for very long periods 

 in soil devoid of leguminous vegetation, and even in air-dry soil. The 

 organism diffuses at a considerable rate through soils that are in proper 

 condition. To secure the bacteria in a soil lacking them, if there is 

 any such, one need only to ascertain the cause preventing their appear- 

 ance, and remove the disturbing factor. 



Oospora buccalis.J — H. Roger, L. Bory, and A. Sartory have in a 

 case of tonsilitis isolated this organism from the white patches on the 

 buccal mucous membrane and also from the pus of the tonsilar abscess, 

 which contained exclusively filaments of Oospora. Pure cultures were 

 obtained in maltose broth ; hanging drops from this showed straight 

 non-motile filaments of various lengths, and ■ 7-0 " 8 jx in width ; when 

 older they become sinuous and wavy, and have irregularly distributed 

 lateral branchings ; on the fourth to fifth day the conidia commence to 

 appear as small hoops, which later become oval and spherical ; the 

 filaments segment into ovoid bodies, probably arthrospores, which at 

 the end of thirty-six hours at 32° to 35° C. give rise to small filaments 

 which soon assume the adult form ; in the old cultures, the filaments 

 which were previously hyaline and homogeneous, become granular, and 

 the branches disappear. 



Aerobic and Anaerobic Growth.§ — A. Meyer notes that the oxygen 

 requirements of organisms is most exactly expressed by three cardinal 

 points of oxygen concentration ; if spores are submitted to lower and 

 lower concentration of oxygen, a point is at last reached at which they 

 no longer germinate, though the potential power of germinating 

 remains ; this point is the minimum oxygen concentration for spore 



* Centralbl. Bakt., 2te Abt., xxiii. (1909) p. 59. 



t Tom. cit., p. 47. 



X C.R Soc. Biol. Paris, lxvi. (1909) p. 301. 



§ Centralbl. Bakt., lte Abt. Orig., xlix. (1909) p. 305. 



