662 SUMMARY OF CURRENT RESEARCHES RELATING TO 



ground illumination. 3. Dependence of resolution of linear objects on 

 the azimuth of the dark-ground illumination. Observation of the 

 spherical aberration of Microscope objectives with the Abbe testplate 

 by means of dark-ground illumination. 5. Distinction between dry- 

 condenser and immersion-condenser. 6. Observation of living bacteria 

 with the paraboloid condenser. 7. Comparison between a paraboloid 

 condenser and a centrally stopped-off immersion-condenser. 



Quekett Microscopical Club. — The 484th Ordinary Meeting of the 

 Club was held at 20 Hanover Square on October 22, the President, 

 Prof. A. Dendy. F.R.S., in the Chair. 



A paper by Mr. J. Rheinberg, F.R.M.S., '• On Resolutions obtained 

 with Dark-Ground Illumination, and their Relation to the Abbe Theory," 

 in the absence of the author, was taken as read. 



Messrs. Heron-Allen, F.R.M.S., and A. Earland, F.R.M.S., gave a 

 lecture on " The Foramiuifera in their role as World Builders." The 

 earliest geological records of the gnmp were quoted, and the develop- 

 ment of the Foramiuifera up to their " golden age" in Eocene times was 

 traced. Here they reached their maximum development both as regards 

 size and abundance, and left their remains in great beds, often of 

 enormous thickness and extending across whole continents. With the 

 passing of the Eocene period, the Foramiuifera rose to their all-important 

 position as rock- builders, although at the present day the area of the 

 Glohigerina ooze, estimated by Murray and Renard at 49i million miles, 

 exceeds in extent even the Nummulitic limestones of Southern Europe, 

 Western Asia, and the Himalayas. Of the thickness of the Globlgerina 

 ooze we can, of course, form no idea, but as the great oceans in which 

 it is being laid down are practically permanent, it must be very great, 

 because we know from deep-sea deposits which have been elevated in 

 Malta, Barbados, Australasia, and elsewhere, that similar deposits have 

 been forming in the deep-sea ever since at least Miocene times. 



B. Technique.* 

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



Medium for Cholera, t — E. Morelli recommends the following 

 medium for cultivating the cholera vibrio : Pancreatina (pepsina or 

 papaina) 2, sodium chloride 0*5, water 100. The pancreatine prepared 

 by Parke, Davis and Co. gave very good results. 



Cultivation of the Cholera Vibrio in Coloured Media. % — E. 

 Signorelli advocates the use of coloured media for cultivating cholera. 

 The medium used is composed of the ordinary agar to which 1 p.c. of 

 the pigment solution is added in the proportion of 1 com. to 5 c.cm. of 

 the agar. The pigments which gave positive results were erythrosin, 

 safrauin, orcein, and dahlia. While other vibrios were affected by the 

 first three, dahlia gave the specific reaction, viz. the decolorizing of the 



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

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

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

 (6) Miscellaneous. 



t Rend. R. 1st. Lombardo, xlv. (1912) pp. 671-5. 



X Gentralbl. Bakt., Ite Abt., Orig., Ixvi. (1912) pp. 469-80. 



