82 SUMM ARY OF CURRENT RESEARCHES RELATING TO 



In the old form the ratio was one-fifth. The length-breadth ratio in 

 the new form is 7 : 5, in the old 8 : 5. 



Wright, F. E.— (1) Graphical Methods in Microscopical Petrography. 



(2) Graphical Plot for Use in the Microscopical Determination of 

 the Plagioclad Feldspars. 



Amer. Joum. Sci., xxxvi. (1913) pp. 509-42 (10 pis.). 



B. Technique.* 

 ^"(DiiCollectiiig' Objects, including- Culture Processes. 



Cultivation of Cladothrix dichotoma.f — The material for culti- 

 vation was obtained from a ditch in the neighbourhood of a sewer. 

 The water was turbid and contained organic impurities. In the month 

 of July a strong growth of green plants was found at the edge of the 

 ditch. Some leaves were taken, examined for the presence of cladothrix, 

 and placed in a • 5 per 1000 meat extract fluid in glass cylinders pro- 

 vided with close-fitting lids. These cylinders were kept, some in day- 

 light, some in the dark. Vorticellae and such types died out within 

 twenty-four hours. After two or three days filaments of cladothrix 

 were seen attached to the leaves. These were freed from the leaves 

 and transferred to fresh fluid. After several such transferences to 

 remove as far as possible extraneous organisms, the filaments were 

 transferred to agar plates containing 0*05 p.c. meat extract. The 

 cladothrix filaments on this medium soon outgrew the other organisms. 

 A pure culture thus obtained was sealed up and kept under anaerobic 

 conditions. It was found alive after two months. 



P. Linde further describes the characters of the culture. It con- 

 tained threads of varying dimensions, and it was thought possible that 

 more than one species was present. Single-filament cultures were 

 examined by means of the Indian ink method, and it was found that 

 the same variations in size were to be observed. 



Egg-broth. :]: — A. Besrekda and F. Jupille have found that many 

 organisms grow well on a medium containing four parts of white of 

 egg (10 p.c. solution) in distilled water, one part of yolk (10 p.c. solu- 

 tion), and five parts of peptone broth. Such organisms as pneumococci, 

 meningococci, gonococci, B. melitensis, and B. pertussis of Bordet and 

 Geno-ou grew luxuriantly, and retained their vitality for several months. 

 On a modified medium, containing 100 c.cm. of broth without peptone, 

 20 c.cm. of white (10 p.c), and 5-20 c.cm. of yolk of egg (10 p.c.) 

 tubercle grew with remarkable luxuriance and rapidity. A tuberculin 



* 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, preservation fluids, etc. ; 

 (6) Miscellaneous. t Centralbl. Bakt., 2te Abt., xxxix. (1913) pp. 372-5. 



% Ann. Inst. Pasteur, xxvii. (1913) pp. 1009-17. 



