ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 773 



Potato Broth for the Culture of Tubercle Bacilli.* — W. Jurewitsch 

 recommends the following preparation of potato broth for the cultiva- 

 tion of tubercle bacilli. Potato is cut in slices and washed and 

 pressed through a sieve ; to 500 c.cm. of this potato mash is added 

 about 500 c.cm. of tap water ; on the following day the mixture is 

 shaken and pressed through linen ; after i to ^ hour the infusion is 

 poured off from the deposit and an equal amount of ordinary 

 " fleischwasser " is added, and also ^ p.c. of pepton and J p.c. of salt 

 solution or calcium phosphate ; the whole is warmed to make a 

 complete solution, boiled for an hour in a Koch's steam apparatus, and 

 filtered. To the filtrate is now added 3 p.c. glycerin and a requisite 

 amount of carbonate of soda to attain the desired alkaline reaction, and 

 the whole is then placed in an autoclave for \ to \ hour at 118-120° C, 

 cooled, filtered, and finally sterilised for h to 1 hour at 115° C. The 

 broth thus prepared should have a dark brown colour ; if it is dark 

 red in tint, it is not sufficiently alkaline, and should be corrected. 



Malachite-green Agar and the Bacilli of the Typhoid Group.-t — 

 L. Padlewsky recommends the following medium for isolating the 

 bacilli of the typhoid group. Ordinary 3 p.c. nutrient agar is mixed 

 with 2 p.c. pepton and 3 p.c. ox-gall and 1 p.c. chemically pure lactose ; 

 the sugar is previously dissolved in a small quantity of distilled water ; 

 the gall is steamed in a Koch's apparatus and filtered through wool ; 

 the reaction of the medium should be slightly alkaline ; it is then 

 divided into 200 or 100 c.cm. flasks and submitted to fractional 

 sterilisation. To 100 c.cm. of the fluid agar, cooled to 60-65° C, is 

 then added the following mixture: — 0*5 c.cm. of 1 p.c. aqueous 

 solution of malachite-green, ' 5 c.cm. of gall, and 1 c.cm. of a 10 p.c. 

 aqueous solution of sulphate of soda. This mixture is not sterilised, 

 but, after thorough mixing, it is poured into dishes and allowed to stand 

 in the open until the agar is solidified, and is then dried in an 

 incubator for 15 minutes. The agar must be transparent yellow in 

 colour and without a trace of green. The fsecal matter is spread on 

 the surface of the agar with a suitable glass spatula. The author 

 claims for this medium that it is the most favourable for a quick and 

 vigorous growth of the bacilli of the typhoid group ; that it has an 

 antiseptic action on many of the other frecal microbes ; and that the 

 colour reaction, whereby the colonies of B. coll and other acid-pro- 

 ducing organisms are stained an intense green, and the colonies of the 

 typhoid group remain colourless, enables the organisms of this group to 

 be readily differentiated ; it is especially useful when large quantities 

 of faecal matter have to be dealt with ; it is easy and inexpensive to 

 prepare. 



Culture in vitro of Avian Plague. + — E. Marchoux has inclosed 

 blood from a fowl dead of avian plague in a sealed capsule, and found 

 that the virulence was retained for a longer time in an ice chamber at 

 7-10° C. than at the temperature of the laboratory or of an incubator, 

 suggesting that in the virulent blood, the antibodies, whose activity is 



* Centralbl. Bakt., lte Abt. Orig., xlvii. (1908) p. 664. 



t Tom. cit., p. 540. % Comptes Rendus, cxlvii. (1908) p. 357. 



