Kingdom Mychota 



[13 



Recent studies of typical bacteria by conventional microtechnical methods (Rob- 

 inow, 1942, 1949; Tulasne and Vendrely, 1947) and by the electron microscope (Hil- 

 lier, Mudd, and Smith, 1949) have made it possible to recognize the essential identity 

 of the structure of their cells with those of the blue-green algae. The protoplast con- 

 sists of outer and inner parts. The outer part, considered as a substance, may be 

 called ectoplasm (Knasyi, 1930), and the inner, considered as a body, may be called 

 the central body (Biitschli, 1890). The ectoplasm is very thin, occupying usually less 

 than one fifth of the radius of the cell. The spiral bands which have often been seen 



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Irx 



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Fig. 1.- — Structure of cells of blue-green algae, a, Symploca Muscorum after 

 Gardner (1906). b, Oscillatoria Princeps after Olive (1904). C, Lyngbya sp. from 

 a slide prepared by Dr. P. Maheshwari, x 1,000. d, Anabacna circinnalis after 

 Haupt (1923) x 2,000. 



in cells of bacteria, and which Swellengrebel ( 1906) mistook for a nucleus, are thick- 

 enings of the ectoplasm. Specific stains for nucleoprotein (chromatin), as Feulgen 

 or Giemsa, usually color uniformly the entire central body. If the cells are exposed to 

 hydrochloric acid, a part of the nucleoprotein, containing ribonucleic acid, dissolves. 

 The remainder, containing desoxyribonucleic acid, persists in the form, basically, of 

 a single fairly large granule in each cell. In rod-shaped bacteria, this granule appears 

 usually to divide by constriction before the cell begins to divide, and may redivide, 

 so that the cell may contain two dumb-bell shaped bodies. De Lamater and Hunter 

 (1951) succeeded in a partial de-staining of the dumb-bell shaped bodies and inter- 

 preted them as dividing nuclei containing centrosomes and definite numbers of 

 chromosomes; typical chromosomes, however, are never as small as the bodies they 

 describe, and are not imbedded in bodies of nucleoprotein from which they can be 

 distinguished only by the most refined technique. Enderlein (1916) observed in rod- 

 shaped bacteria series of granules of which some at least are identical with the dumb- 



