414 CHARLES SLATER. 



Biitschli has advanced the theory that the cell contents of 

 bacteria represent the nuclei of other cells, while the proto- 

 plasm is reduced to an extremely thin layer, in many cases 

 only represented by the cell wall. He bases his views 

 ('Biitschli ueberdenBau der Bacterien, etc./ Leipzig, 1890) on 

 the study of the large flagellated organisms found in sulphur 

 waters, which he shows to possess an internal cell substance, 

 having the structure and staining properties of nuclei, and 

 containing the granules of Ehrlich. The refractive portions 

 of the organism described in this paper are strongly stained 

 by the ordinary nuclear stains, such as alkaline aniline dyes, 

 and especially logwood. On this view the forms which have 

 been described as occurring in young freely growing cultures, 

 viz. the short oval cells with refractive poles occurring either 

 singly or in pairs, would apparently be the forms resulting 

 from direct division, and the polar collections of protoplasm 

 would represent the direct division of the nucleus. The suc- 

 cessive stages of this division would be represented (fig. 4, a) 

 by — 1, the cell, with refringent poles ; 2, a form resembling a 

 large diplococcus, stained throughout, and formed by division 

 of stage 1 — this form occurs but rarely; 3, a bicellular 

 organism found by the growth of stage 2. In this third stage 

 the cell stains at first equally throughout, but soon, either 

 before the cells separate or soon afterwards, the protoplasm 

 collects at the poles, i. e. the nucleus divides directly, and 

 stage 1 is reproduced. The division of the cell in stage 1, and 

 the formation of stage 3, have been directly observed. 



Dr. Delepine, who kindly examined some of the specimens, 

 suggested that some of the other appearances were due to 

 karyokinesis, and, having regard to the columnar form of the 

 organism and its small size, various forms may be distinguished 

 which would represent the formation of a central plate and its 

 subsequent division and gradual separation. These forms are 

 represented in fig. 4, b. Starting with a cell, whose contents 

 stain equally and moderately, these contents representing a 

 nucleus, there is a gradual gathering of the chromatin until 

 an intensely staining central plate is formed with unstained 



