Report on the Bacteriology of Water. 271 



In a 3 per cent, solution of glucose, to which a little broth and 

 Liebig's extract (mere traces) are added, the cultures at 20 C. show 

 rapid growth in twenty-four hours as white cotton- wool- like flocks, 

 resembling those formed in broth. 



Further research has shown that it grows readily in and on all 

 ordinary media, at all temperatures from 12 15 C. up to 27 30 C., 

 the optimum being near 25 C. But it is also capable of slow growth 

 at temperatures below 7 or 8 C., and even above 38 39 C. for a 

 short time. It is not strictly aerobic, but nearly so, and yields no 

 pigment or other pronounced excretion. 



I owe to the kindness of Dr. W. S. Lazarus-Barlow, of the 

 Pathological Laboratory, Cambridge, the following proof that this 

 organism is not pathogenic : 



" The question whether the bacillus were pathogenic or non-patho- 

 genic was investigated on mice and on guinea-pigs. Beef-broth- 

 cultures of ages varying from one to seventy-eight days, and in 

 quantities of 2 c.c. in the case of the mice and 20 c.c. in the case of 

 guinea-pigs, were used. The mice were inoculated sub-cutaiieously, 

 and the guinea-pigs intra-peritoneally. In no animal was any devia- 

 tion from the normal observed except such as were directly and 

 solely attributable to the introduction of the aseptic needle of the 

 syringe. The bacillus is therefore non-pathogenic. This conclusion 

 is further supported by the fact that the bacillus grows better at the 

 room-temperature than at the body-temperature." 



I have to record my thanks not only to Dr. Lazarus- Barlow for the 

 trouble he took in the above investigation, but also to Professor Boy 

 for permitting the investigation in his laboratory. 



Characters of Bacillus ramosus (Fraenkel). 



Habitat 



Morphology 



Thames water, especially iu autumn and winter, but also 



in summer. 



As long, straight, or curved filaments, often twisted into 

 tresses ; subsequently breaking up into segments 

 (bacilli). Diameter of filaments = 1'75 /u, length 20, 

 50 to 100 jtt or more. Bacilli 3 to 6 fi x 1'75 n, with 

 rounded ends, often in long chains. Forms spores = 

 1'75 to 2 /* x T5 fj.. 



Movements Not motile, but the growing filaments exhibit slight 



nutation movements. 



Colonies on gelatine 



: /i 



plates at 15 C. 





Appear in two days as circular, ill-defined, mould-like, 

 white, rapidly-growing membranes. In three days 

 may attain 25 mm. diameter ; in ninety-six hours = 

 50 mm. ; in six days 75 mm. or more. Mycelial-Kke 

 membrane radiately veined with thicker and thinner 

 strands of woven filaments, like a root-system or 

 myxomycete plasmodium : slowly liquefies from about 

 the third day. 



