BACILLI 483 



RHINE WATEE BACILLUS ' (Burri) 



I LIQUEFIES GELATINE I 



Authority. Burri, Ueber einige zum Zwecke der Artcharakterisirung an- 

 zuwendende bacteriologische Untersuchungsmethoden nebst Bcschreibung von 

 zivei neuen aus Rheinwasser isolirten Bacterien, Muenchen, 1893 (Olden- 

 bourg). 



Where Found. In the river Khine in the vicinity of Cologne. 



Microscopic Appearance. Bacilli about 2| to 3| //. long and about f p. broad, 

 with rounded ends ; some isolated individuals are slightly bent. In broth cul- 

 tures from one to two days old threads are found varying from 5 ft to 10 /u, and 

 even reaching 90 p. in length, and from | to | /u broad. Under a high power 

 these threads are apparently made up of short or longer elliptically shaped 

 individual bacilli. No spore formation observed. In the presence of a suf- 

 ficient supply of oxygen the bacilli, occurring both singly and in pairs, are 

 capable of rotatory as well as forward movements, but the threads are motionless, 

 as are also those bacilli taken from cultures only sparsely supplied with air. 

 No flagella could be detected by Loemer's method. Stains readily with the 

 ordinary aqueous solutions of aniline colours. 



Cultures. 



GELATINE PLATES. The colonies in the depth resemble dirty -yellow dots. 

 The surface colonies during the first three days are colourless and transparent, 

 but later they assume a yellow colour, which extends in a lesser degree to the 

 adjacent gelatine, the convex shape disappears, and they become bright yellow 

 centres surrounded by a zone of clear liquid gelatine (on very crowded plates 

 the whole of the gelatine is liquefied in a week). The colonies are so compact 

 that they can be entirely removed from their fluid surroundings on the needle's 

 point. Under the microscope the periphery of the surface colonies is wavy 

 and the contents rough and irregular ; the centre is yellowish, whilst the rim is 

 transparent and grey, but after three days it also becomes yellow. The depth 

 colonies are circular and smooth-rimmed, with granular contents. 



GELATINE TUBES. Produces a liquid depression wider at the surface than in 

 the depth of the tube, and on the surface the still solid gelatine acquires a 

 bluish grey opalescence. Yellow masses of bacteria collect at the bottom of 

 the depression, and a few flocculent particles float on the surface, but no real 

 pellicle is formed. In the depth of the gelatine the growth is very scanty, in 

 consequence of the limited supply of air. 



GLYCERINE-AGAR. Produces in streaked cultures a thin, shining, honey- 

 coloured expansion, which is dry and tough. 



POTATOES. Forms a moist, shining, thin, flat, orange or rust-coloured expan- 

 sion. The colour only becomes bright orange after about six days, if the inocu- 

 lation is made from a quite young broth culture. 



BKOTH. Benders it turbid, and produces a thick bright orange-coloured 

 pellicle, and a yellow deposit. After fourteen days the liquid becomes almost 

 quite clear, and on shaking the tube the pellicle breaks up into small pieces, 

 which nearly all sink to the bottom. Microscopically the pellicle is seen to 

 contain the short bacillar forms, but in the liquid only the long worm-like 

 threads are found. 



MILK. The milk is only partially coagulated in the upper part of the tube, 

 and the layer of cream floating on the surface assumes a pale yellow colour, 

 which becomes deeper with age as a tough pellicle forms. The serum beneath 

 the pellicle gives a faint alkaline reaction. 



Remarks. It grows well at from 15 to 20 C. , but will not develop at 37 C. Broth 

 cultures seven days old, exposed for five minutes to a boiling temperature, are 

 destroyed, similar results being obtained when such cultures were kept for half an 

 hour at 60 C. If the culture tube is covered with an india-rubber cap, and the 

 access of air prevented, the bacilli very soon die. No formation of gas observed in 

 any of the culture media, even when an addition of dextrin was made. Grows best 

 when the culture material contains about 0'05 per cent, of carbonate of soda. 



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