596 A MANUAL OF BACTERIOLOGY 



motile forms. His procedure is to make use of a special alkaline 

 peptone medium, which is placed in a glass jar. In this is immersed 

 a Pasteur-Chamberland filter-candle half filled with the same 

 solution, to which is added a little of the fluid to be examined, and 

 the whole is incubated at 37 C. Sooner or later growth appears 

 in the fluid outside the candle, and Cambier states that if typhoid 

 bacilli be present they will make their appearance before B. coli. 

 In hands other than those of Cambier, however, the method has 

 not proved successful. 



7. Fuchsin agar (Endo). One litre of 3 per cent, nutrient agar 

 is made alkaline with 10 c.c. of 10 per cent. NaOH solution after 

 neutralisation. Pure lactose 10 grm. and saturated alcoholic 

 fuchsin solution 5 c.c. are added, and after mixing, 25 c.c. of fresh 

 10 per cent, solution of sodium sulphite are added. The medium 

 when cold should be colourless. The medium is used as surface 

 plates, and on it typhoid and paratyphoid colonies are colourless, 

 coli colonies are red. 



8. Malachite-green media. Loffler has found that malachite 

 green (No. 120 Hoechst) in the proportion of about 1 in 5000 in 

 media inhibits the growth of B. coli while still permitting the 

 growth of B. typhosus. The dye may be added either to liquid or 

 to solid media. The medium recommended by Loffler l is com- 

 posed of 3 per cent, agar made with meat infusion, with 1 per cent, 

 nutrose, and containing in every 100 c.c. 2-2-5 c.c. of a 1 per cent, 

 solution of malachite green. On this medium the B. typhosus 

 grows in twenty-four hours as delicate, slightly crinkled colonies, 

 surrounded by a colourless zone (due to alkali formed by the bacilli). 

 Thus it is possible to detect one colony of B. typhosus among 300 to 

 600 colonies of other bacteria. As a medium for " enriching "- 

 i.e. for specially advancing the growth of the B. typhosus Loffler 

 recommends a 15 per cent, gelatin, prepared with beef -juice and 

 peptone, and containing per 100 c.c. 3 c.c. of doubly normal phos- 

 phoric acid and 2 c.c. of 2 per cent, malachite-green solution. With 

 the suspected matter, firstly, one series of malachite -gelatin plates 

 is prepared and incubated at 25 C. for twenty to twenty-four 

 hours ; secondly, a tube of malachite gelatin is inoculated and 

 incubated at 37 C. for twelve to twenty-four hours ; from this a 

 second tube is inoculated and incubated at 37 C., and then plated 

 out on malachite gelatin and incubated at 25 C. The colonies of 

 B. typhosus are well marked after twenty to twenty -four hours, as 

 large as a pin's head, transparent, highly refractile, light grey and 

 granular. Their shape is circular or oval, and they show charac- 



1 Deutsch. med. Woch., 1906, No. 8. 



