488 :miciio-organisms ix avatek 



BACILLUS THEEMOPHILUS 



Authority.^Miquel, ' Monographie d'un Baeille vivant au-dela de 70° C.,' 

 Annales de Micrographie sj)6cialetnent consacr4es a la BacUriologie, aux Proto- 

 phytes et aux Protozoaires^ Paris, No. 1, 1888, p. 3. 



Where Found. — Occasionally in air. Found frequently in river-water, but 

 not in spring -water. Very prevalent in sewage-poUnted water. Miquel found 

 as many as 1,000 in 1 c.c. of river Seine water collected at the bridge of Auster- 

 litz in Paris, and many more in the river-water below Paris. Its normal habitat 

 appears to be drain-water. It ,is also found in soil, as well as in the alimentary 

 canal of man and animals. If drops of drain-water be inoculated into broth- 

 tubes subsequently maintained at about 69° C, they become turbid in twenty- 

 four hours, and in nearly all cases contain the B. thermophihis. 



Microscopic Appearance. — The dimensions of the bacillus vary according 

 to the temperature at which it is cultivated. Thus at 50° C. it is usually short, 

 and exhibits an oval spore at the end of the rod. At 60° C. it forms filaments, 

 and only a few spores are visible. At 70° C. the filaments acquire a granulated 

 appearance. At 71° to 72° C. no spores are found, and the bacillus is swollen 

 and resembles a necklace. It is not motile. 



Cultures, — 



Agar-agar TuBES.^It will neither grow on gelatine at from 22° to 23° C, nor 

 on agar-agar between 30° and 40° C. At 42° to 45° C. a white raised meniscus- 

 shaped growth is visible on the agar. Microscopic examination reveals the 

 presence of a short plump bacillus, with a very highly refracting spore at one 

 end. 



Broth. — No growth at 40° C, even when preserved at this temperature for 

 thirty days, but at 42° C. and beyond the liquid becomes turbid in three to four 

 days, and at 50° C. in forty-eight hours, and still earlier at 60° C, when cloudy 

 isolated patches appear in the broth. It grows best at from 66° to 70°. At 71° C. 

 the appearance of turbidity only commences after two days, whilst at 72° C. it 

 grows very badly. At the most favourable temperatures an abundant precipi- 

 tate forms at the bottom of the tube, and the liquid becomes clear. 



Bemarks. — It is not pathogenic to animals. When the temperature of the water 

 is raised beyond 50° C. it becomes an active putrefying agent. The fact that it is 

 found in the alimentary canal indicates, says Miquel, that it is capable of growing 

 slightly between 37° and 40° C. 



