156 BACTERIOLOGICAL EXAMINATION OF WATER. 



waters, but do not appear to be present in pure waters. In 

 1888 Globig showed that a number of bacteria were capable of 

 growing at a temperature of 50 to 70 C. He isolated these 

 organisms by inoculating potatoes with soil, and then incubating 

 them at varying temperatures. In the same year Miquel 

 described the B. thermophylus, which he found to be very 

 prevalent in sewage-polluted water, as many as 1000 per c.c. 

 being detected in water from the Seine collected at the Bridge 

 of Austerlitz. According to Miquel the organism was not 

 present in spring-water ; it was occasionally found in air, but its 

 normal habitat appeared to be sewage. When drops of drain- 

 water were inoculated into broth, and then maintained at 69 C., 

 the medium was found to become turbid in twenty-four hours, 

 and contained the B. thermophylus. On agar at 452 to 45 C. 

 the bacillus gave rise to a white raised meniscus-shaped growth, 

 which, on microscopic examination, showed the presence of a 

 short, plump bacillus, with a highly refracting spore at one 

 end. In broth it grew best at a temperature of 65 to 70 C., 

 and produced an abundant white deposit at the bottom of the 

 tube, the liquid above becoming clear. The microscopic appear- 

 ance of the bacillus appeared to vary with the temperature at 

 which it was cultivated. At 50 C. the bacillus was short, with 

 an oval spore at one end ; at 60 C. it formed filaments, and 

 only a few spores appeared; at 71 to 72 C. no spores were 

 found, and the bacillus appeared swollen. It was not motile, 

 and produced no pathogenic effects in animals. In 1894 

 Macfadyen and Blaxall isolated thermophylic bacteria from 

 specimens of earth, derived partly from the surface and partly 

 from depths up to five feet. They also found the organisms in 

 Thames mud and in faeces from human beings and mice. In 

 1895 Rabinowitsch repeated and extended Macfadyen and 

 BlaxalPs work. This observer used potato as the nutrient 

 material for isolating the bacteria. After twenty hours incu- 

 bation at 62 C. four to eight white colonies appeared on the 

 inoculated potatoes ; after forty hours incubation yellowish- 

 grey, brown, and reddish-brown colonies also developed. Pure 

 cultures were obtained by inoculating the growths on plates 

 containing three per cent. agar. The thermophylic bacteria 

 were found in earth, snow, the River Spree, and in the excre- 



