610 SUMMARY OF CURRENT RESEARCHES RELATING TO 



removed further from or brought nearer to the radium by means of 

 the milled head on its circumference ; each complete turn of the screw 

 removes the screen 1 mm., and the head being marked in tenths of its 

 circular distance allows a variation of tenths of a millimetre ; the screen, 

 when placed its nearest position, is 1 mm. from the radium. 



Brass, Dr. A. — Der Scheiner'she Versuch. 



[An historical article on the optical work of Professor Scheiner, S.J., of 

 Ingolstadt, who lived at the beginning of the seventeenth century.] 



Central.-Zeit. f. Opt. u. Mech., xxvii. (1906) pp. 163-5 (1 fig.). 



Weinschenk, E. — Anleitung zum Gebrauch des polarisationsmikroskops. 



Freiburg : Herder, 2nd ed., enlarged and revised, 1906, 

 viii. and 148 pp., 135 figs. 



B. Technique.* 

 (1) Collecting: Objects, including- Culture Processes. 



Anaerobic Nitrogen-fixing Organisms.f — E. Haselhoff and Gr. 

 Bredemann have examined various soils and leaves of different trees — 

 birch, oak, beech, etc. — and found anaerobic nitrogen-fixing organisms 

 in almost every case. The material was placed in water, heated for 

 three minutes at 80° C, and then placed in Winogradsky's nitrogen-free 

 medium in a nitrogen-containing atmosphere, and incubated at 28° C. 

 From these rough cultures pure cultures were obtained. Cultures were 

 also obtained in flasks through which nitrogen was conducted, the 

 amount of the nitrogen fixed being estimated by comparing the nitrogen 

 content of the flask before and after the fermentation produced by the 

 organism. The five different Clostridia cultivated from the soil and 

 foliage were very similar, but none were identical with G. pasteuri. 



Use of the Sodium Salt of Nucleinic Acid in Bacteriological 

 Diagnosis.* — A. Pepere finds that the solid media of liver-broth gelatin, 

 to which has been added the sodium salt of nucleinic acid, affords a 

 certain means for the differential diagnosis of B. typhosus and B. coli. 

 In the case of B. coli the medium is readily liquefied, whereas in the case 

 of B. typhosus not the slightest peptonising action occurs. 



Culture of Treponema pallidum. t — Gr. Leuriaux and V. Greets ob- 

 tained cerebro-spinal fluid by lumbar punctures under strict asepsis, from 

 cases of secondary syphilis, and, after adding neutral pepton broth, 

 incubated the mixture at 37° C. for 3-4 days. Hanging drops from 

 these cultures showed the presence of minute rapidly-motile corpuscles. 

 The liquid was centrifugecl for 20 minutes, and the deposit inoculated 

 on solid pig serum. After 3-4 days there appeared on the surface of 

 the medium an ivory-white moist sticky layer, with a strongly alkaline 

 odour. Out of forty-two punctures three typical cultures were obtained. 

 Cover-slip preparations from 5 -day old cultures were stained by Crieinsa's 



* This subdivision contains (1) Collecting Objects, including Culture Pro- 

 cesses ; (2) Preparing Objects; (3) Cutting, including Imbedding and Microtomes ; 

 (4) Staining and Injecting ; (5) Mounting, including slides, preservative fluids, etc. ; 

 (6) Miscellaneous. f Bot. Zeit., 2te Abt., 1906, p. 234. 



J Centralbl. Bakt., lte Abt. Kef., xxxviii. (1906) p. 267. 



§ Centralbl. Bakt., lte Abt. Orig, xli. (1906) p. 684. 



