ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 109 



Preparing and Staining Pollen." Mr. A. 0. Banfield gave a lecture, 

 with lantern illustrations, on " Low-power Photomicrography and 

 Stereo-Photomicrography." Mr. James Murray exhibited some specimens 

 of Rotifers obtained by the ' Nimrod ' during Shackleton's Antarctic 

 Expedition. 



The 460th Ordinary Meeting was held on Tuesday, November 23. 

 Reference was made to the much-regretted death on November 7 of Dr. 

 W. H. Dallinger, F.R.S., etc., Member and Past President of the Club. 

 The President exhibited and described two preparations of cysticercus of 

 tapeworm, probably Hymenolepis diminuta, obtained from rat fleas. 

 Note of a new locality, the second known, for Zoothamnium {/eniculatum 

 was communicated by Mr. J. Stevens, F.R.M.S. Mr. F. P. Smith con- 

 tributed a " Note on the Mounting of Spider Dissections as Microscopical 

 Objects." Mr. J. S. Dunkerley, B.Sc, gave an interesting resume of 

 our knowledge of that little-known group of the Protozoa, the Choano- 

 flagellata. J. Clark, in America, was the first to describe the true 

 structure of these forms. A typical Choanoflagellate has an oval, naked, 

 protoplasmic body with nucleus, contractile vacuole, one flagellum, and 

 surrounding the base of the flagellum a protoplasmic membrane — the 

 collar — which is usually basin-shaped. The flagellum arises from a 

 staining granule, the blepharoplast, which apparently was not seen by 

 Saville Kent and other early workers. 



B. Technique.* 

 Uncollecting Objects, including: Culture Piooesses. 



Two New Methods for Growing Azotobacter in large quantities 

 for Chemical Analysis.f — C. Hoffman and B. W. Hammer describe two 

 procedures by which they have obtained good results. 



1. For obtaining a large amount of Azotobacter cells an adaptation 

 of the old " pinsel " plate culture method has been employed. In large 

 8 or 11 in. Petri dishes, \ in. layer of the specific agar medium is 

 placed ; the whole is then sterilised and finally cooled. The plates are 

 then inoculated with a heavy suspension of Azotobacter in sterile water, 

 using about 10 c.cm. per plate. This is thoroughly and evenly dis- 

 tributed over the surface of the solidified agar, and the cultures so pre- 

 pared then incubated. Under these conditions thorough aeration is 

 possible. After the necessary period of incubation the growth, which is 

 very abundant, is carefully scraped off the surface of the agar with a 

 glass slide, removed to an evaporating dish, and prepared for chemical 

 analysis. As much as 1 grm. of dry growth per plate has been obtained 

 in this way. 



2. To study the influence of different chemical compounds upon the 

 nitrogen-fixing properties of Azoterbacter, the authors devised their "sand- 

 slope " culture. This consists in using clean washed and heated quartz- 



* 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. 



t Centralbl. Bakt., 2te Abt., xxiv. (1909) pp. 181-3. 



