ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



727 



best made by trial on the focusing screen, for if each of the two 

 negative images is fairly well centred in its own half of the plate, a 

 convenient mounting separation will generally be secured. 



Quekett Microscopical Club. — The 433rd Ordinary Meeting of the 

 Club was held on October 19, the President, Dr. E. J. Spitta, F.R.A.S., 

 F.R.M.S., in the chair. 



Mr. C. F. Rousselet, F.R.M.S., gave a corrected description, and 

 exhibited a specimen from the Matoppo Hills, Rhodesia, of the rare 

 Rotifer Tetramastix opoliensis. 



Mr. Jas. Burton read a paper " On the Reproduction of Mosses and 

 Ferns.'" 



B. Technique.* 

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



Doulton's White Porcelain Filter.f — W. Bullock and J. A. Crau 

 have tested the filter recently introduced by Doulton and Co., of 

 Lambeth, using as control the Chamberland F. Filtration experiments 



Pig. 81. 



at low pressure showed practically no difference between the two filters. 

 Tested by means of the vacuum pump, it was found to be eminently 

 suited for obtaining sterile filtrates in the laboratory. Under high 

 pressures (taps and mains) the results were quite as satisfactory as those 

 obtained by other filters, but the candle was occasionally liable to break 

 at the base, a defect remediable by making the candle a little thicker. 

 The illustration (fig. 81) shows the apparatus fitted up for laboratory 

 work. 



Medium for Cultivating Delicate Microbes.} — 0. Bordet and 

 0. Gengou have cultivated successfully the bacilli of whooping-cough 



* 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. + Journ. Hygiene, vi. (1906) pp. 409-20 (4 figs.). 



X Ann. Inst. Pasteur, xx. (1906) p. 734. 



