ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 357 



are round or rod-like, straight, bowed or irregular, single or joined 

 in pairs or chains ; optimum temperature is 28'^ C. 



B. xylinum on wort-agar forms moist, light brown round colonies^ 

 raised at the centre and with granular surface ; the pellicle formed on 

 fluid media is at first clear, later whitish, thick, and leathery, and in 

 cultures several days old it cannot l)e broken by the platinum needle. 

 The cells are usually elongated, short or long rods, or threads, often 

 spirally or irregularly curved ; it grows well at 26''-82'^C., and in sugar- 

 yeast water at ?>5°-38° C. 



Colouring-matter of Bacillus pyocyaneus.* — J. de S. Palma observed 

 on the surface of agar cultures of B. pyocyaneus small pale greenish-yellow 

 needle-like crystals arranged in rosettes, the medium itself being dark 

 green and later becoming brown. From month-old cultures the colouring^ 

 matter was extracted with chloroform, and after evaporation a brown- 

 green mass was obtained, which when treated with alcohol became green 

 in colour ; the undissolved remains were repeatedly washed and crystal- 

 lised from warm dilute alcohol, and clear pale yellow needles with a fusing 

 point of 239° C. resulted. 



By growing the organism on various chemical media it was shown 

 that neither sulphur nor magnesium were required for the production of 

 the green colour. The above described yellow substance was treated 

 with oxidising reagents without result, but a green coloration was 

 obtained with reducing agents. 



Pathogenic Violet Bacillus .f — M. A. Gauducheau isolated from well 

 water a violet bacillus resembling B.jantlimwn (Zopf) and 5. violaceus 

 manike (Wooley). The organism is 1-8 fx long, motile, does not stain 

 by Gram's method, and only with difficulty by methylen-blue, but is 

 readily stained by crystal-violet and carbol-fuchsin : it grows rapidly on 

 agar, broth, and potato at 20° C, more slowly on gelatin, which is 

 liquefied ; it coagulates milk and re-dissolves the casein ; agar and potato 

 cultures have a violet colour, and broth is clouded and has a violet 

 pellicle ; the cultures have an odour of bitter almonds. 



The violet pigment is insoluble in water, ether, and chloroform, but 

 is soluble in alcohol ; it changes to green on the addition of soda. 

 Introduced into a guinea-pig, the temperature of the animal is lowered 

 by more than 10°, and death results. It is also pathogenic to rabbits. 

 Subcultures of some colonies taken from the rabbit after death produced 

 no pigment in broth, and the organism then appeared identical with 

 B. janthinum. 



Creatinin-forming Bacteria.^ — N. Antonoflf differentiates certain 

 bacteria according to their property of forming creatinin. To 5 c.cm. 

 of a killed pepton-water culture is added 1-2 c.cm. of a 15 p.c. solution 

 of caustic soda, and 7 drops of a freshly-prepared 10 p.c. solution of 

 nitro-prussiate of soda ; the presence of creatinin turns the fluid a ruby- 

 red colour, which after 1-5 minutes changes to straw-yellow, and on 

 acidifying with acetic acid it becomes green and gradually blue. 



* Centralbl. Bakt., It- Abt. Orig., xliii. (1907) p. 417. 



+ C.R. Soc. Biol. Paris, Ixii. (1907) p. 278. 



X Centralbl. Bakt., Ite Abt. Orig., xliii. (1907) p. 209. 



