ZOOLOCV AM) JiOTANY, .MKROSCOPY, ETC. O.'U 



D. J. Scourfield gave a resume of a paper by James Murray, F.R.S.E., 



on the Gastrotriclia, a small uroupof minute animals, chiefly fresh-water, 

 of doubtful affinity. 'J'he various sections of the paper (lescribe their 

 form and structure, their haunts and habits, an historical sketcli of the 

 group and classification, a key to the genera and species, with a list of 

 all the eighty-three species whicli have'been described, and an aimotated 

 bibliography. 



E. M. Nelson on " An Improved Form of Cheshire's Apertometer." 

 A number of short arcs of circles of varying radii are employed, avoiding 

 the confusion of many complete concentric circles, and permitting the 

 N.A. to be obtained to the second decimal place with a fair amount of 

 accuracy. 



F. J. Cheshire did not think the form of apertometer he had de- 

 scribed some ten years ago Avas capaljle of greater accuracy. He then 

 described, and subsequently demonstrated, another and more direct 

 method of measuring N.A. 



M. A. Ainslie also read a paper on " A Variation of Cheshire's 

 Apertometer," designed to ensure fair accuracy in reading to the second 

 decimal place. 



Wright, F. E.— Graphical Methods in Microscopical Petrography. 



A77ier. Journ. Sci., xxxvi. (1913) pp. 509-39 (8 pis.). 



,, ,, A Graphical Plot for use in the Microscopical Determination of 

 the Plagioclase Feldspars. 



A77ier. Journ. Sci., xxxvi. (1913) pp. 540-2 (1 pi.). 



Far WELL, H. W. — Optical Bench for Elementary "Work. 



Amer. Journ. Sci., xxxvi. (1913) pp. 473-4 (1 fig.). 



B. Technique.* 

 (1) Collecting- Objects, incltiding- Cultvire Processes. 



Selective Medium for the Paratyphoid-enteritidis Group. f — 

 J. C. Torrey recommends the use of brilliant green broth as a specific 

 enrichment medium for the organisms of this group. After trying 

 various strengths of brilliant green in combination with various degrees 

 of acidity of broth, he found the following to give the best results. 

 Meat-peptone-broth is titrated to the neutral point for phenolphthalein, 

 and 1 p.c. glucose is added. The fluid is tubed in lo c.cm. quantities 

 and sterilized. A 1 p.c. solution of brilliant green (Griibler's) is prepared, 

 and just before use O'lT) c.cm. of this solution is added to each tube. 

 This gives a concentration of the dye sufficient to inhibit or destroy the 

 dominant fnecal bacteria, without interfering with the growth of para- 

 typhoid and allied bacilli. A very slight increase in the acidity of the 

 broth, in the presence of brilliant green in this strength, will, however, 

 inhibit or kill these organisms also. 



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

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

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

 (6) Miscellaneous. 



t Journ. of Infectious Diseases, xiii. (1913) pp. 263-72. 



