THE BIOLOGY OF MICROBES, ETC. 169 



motile, bent and curled in various ways, and they 

 have rounded ends. They are distinctly articulated 

 (16 //, broad), and contain sulphur granules. 



Besides the four last-mentioned microbes there 

 are B. leptomitiformis y B. arachnoidea, and B. pel- 

 lucida, each of which contains sulphur granules. 

 These microbes play an important part in the elimi- 

 nation of sulphur and the disengagement of sul- 

 phuretted hydrogen. The sulphogenic or sulphur- 

 forming microbes are found in certain waters, and 

 many of the natural sulphurous waters are due to 

 the action of these microbes on alkaline sulphates 

 and organic matter present in such water. The 

 decomposition of calcium sulphate by sulphogenic 

 microbes may be represented by the following 

 equations : 



(a) 3 CaS0 4 + H 2 = S 2 + H 2 S + 3 CaO + 5 2 . 

 (ft) 2 CaS0 4 = S 2 -|- 2 CaO + 3 2 . 



Sulphogenic microbes are also capable of decom- 

 posing animal and vegetal albumin with the libera- 

 tion of sulphur. 



Bacillus septicus. This microbe occurs in soil, 

 putrid blood, and other fluids. Its breadth varies 

 from 4 to 10 /i, and its length depends on the 

 number of elements contained in a row : the shortest 

 are about 4 /z. It is a non-motile bacillus, capable 

 of forming leptothrix and spores. 



Bacillus of conjunctivitis. This bacillus was 

 obtained from the conjunctival sac in cases of con- 

 junctivitis. It grows on agar-agar plates as pearly 

 dots, and in bouillon. The latter medium is the 



