i64 SULPHUR BACTERIA 



clusters, regular or otherwise, would be placed in the genus 

 Sarcina, but under different conditions the same organism 

 may be found as uni- and diplo-cocci, when it could equally 

 find a place in the genera Micrococcus or Streptococcus. Hence 

 among the Coccacece an organism made up of groups of very 

 small denomination cannot be placed until it is determined 

 whether its division walls are found in three planes. In some 

 cocci this is undoubtedly the case, for the writer has observed 

 in some, three division walls, mutually perpendicular, to be 

 sinmltaneously present in the same coccus. It is felt, however, 

 that in the vast majority of cases, organisms have been 

 allocated to the genus Sarcina without ascertaining whether 

 division took place in three planes. It has been assumed 

 that because the organism was found in clusters it underwent 

 this form of division. No investigation of the number of 

 planes of division of any bacterial organism has been made to 

 determine the constancy of the number, and yet differences 

 in the number of planes of division have taken an important 

 place in the classification of bacteria. 



The irregular arrangement of the globular cells of the 

 sulphur bacteria embedded in slime suggests the possibility 

 that these organisms may be classed as Sarcina, but since no 

 investigation of the number of planes of division has been made, 

 this is a mere speculation. 



Genus i. — Thiocapsa (Winogradsky). 



Literature. — Winogradsky (2), 1888 ; Migula (3), 1897 ; 

 Bergey, 1923 ; Bavendamm, 1924. 



Description. — One species only, namely Thiocapsa roseo- 

 persicina. The cocci which make up the organism are en- 

 closed in slime and are about 2-8/x in diameter. The slime 

 ultimately liquefies and the enclosed individuals escape. 

 They are non-motile, and each settles down and forms a fresh 

 envelope of slime. Multiplication is by fission. The colour 

 is intense rose-red, and the cells are rich in sulphur inclusions. 

 Winogradsky observed the development of a zoogloea for a 

 period of six months, and found no change in its condition. 



