ZOOLOGY AND BOTANY MICROSCOPY, ETC. 367 



sterile broth is blue, the broth in the tube containing the Klebs-Loeffler 

 bacillus at once assumes a ruby red colour, and that in the tube con- 

 taining the pseudo-diphtheria bacillus after a few minutes becomes green. 

 After twelve hours' further incubation, however, this last will also give a 

 red colour. 



Differentiation of B. coli and B. typhosus.*— R. Zielleczkey, in 

 differentiating B. coli from B. typhosus, employs the following medium 

 in place of Petruschky's " Lakmusmolke " : ordinary nutrient broth, in 

 which has been dissolved 1 p.c. agar with the addition of 0*1 to 0'5 of 

 a solution of phenolphthalein to every 5 ccm. of medium. The phenol- 

 phthalein solution is prepared by dissolving ■ 5 gram phenolphthalein 

 in a mixture of 50 ccm. absolute alcohol and 50 ccm. distilled water, and 

 then diluting the fresh solution to twenty times its volume with distilled 

 water. In this medium the B. coli produces a colour change in from 

 5 to 8 or 9 hours, whilst the B. typhosus does not produce any 

 change until after about 15 hours. 



Anaerobic Cultivations.f — D. Rivas claims to have simplified 

 anaerobic methods of cultivation by the use of media containing 

 sulphindigotate of soda and freshly prepared solution of ammonium 

 sulphide. The author makes his fresh ammonium sulphide solution in 

 a similar manner to that suggested by Hammerl,! and adds it in the 

 proportion of 5 p.c. to feebly alkaline broth, gelatin, or agar containing 

 1*5 p.c. peptonand 1 p.c. glucose. Two cubic centimetres of a 10 p.c 

 solution of sulphindigotate of soda in sterile distilled water are then added 

 to the medium per litre. Another medium employed in his experiments 

 was prepared in a similar manner to the above, but 50 ccm. of a 1 p.c 

 solution of sodium sulphide was substituted for the ammonium sulphide. 

 This, however, did not give quite as good results. 



Glass test-tubes, each provided with a constriction at the junction 

 of its middle and lower thirds, somewhat similar to Roux's potato 

 culture tubes, were employed in Rivas' experiments. After filling the 

 medium into the tubes almost to the level of the constrictions and 

 sterilising, the medium was inoculated and the upper surface of the 

 inoculated medium covered with a layer of sterile oil to prevent access 

 of oxygen to the culture. The author by these means was able to 

 obtain good cultivations of the bacilli of tetanus and of malignant 

 oedema and other obligate anaerobes. 



Differentiation of B. typhosus and B. coli.§ — Mabel P. Fitzgerald 

 and G. Dreyer contribute a paper of extreme importance in which they 

 describe the results of their experiments to elucidate the character of the 

 so-called coli-reaction observed when the B. coli is grown in media 

 coloured with neutral-red. They find the reaction is a quantitative and 

 not a qualitative one, which can be obtained with Grubler's neutral-red 

 and to a less extent or not at all with other commercial brands. Glucose- 

 free bouillon tinted with neutral-red is a preferable medium to agar ; 

 whilst media having an acid reaction corresponding to more than 0'5 p.c. 



* Ceutralbl. Bakt., l te Abt. Orig., xxxi.(1902) pp. 752-68. 



t Op. cit., xxxii. (1902) pp. 831-42. t See this Journal, 1902, p. 370. 



§ Festskrift Statens Serum Inst. Copenhagen, 1902. 



2 b 2. 



