C. F. Robinow 



421 



multiply by splitting lengthwise in a plane more or less 

 parallel with the short axes of the bacterium. 



3. The chromatinic structures of Bact. coli and of 

 Proteus vulgaris are essentially the same as those pre- 

 viously described in myxobacteria and actinomycetes 

 (Badian, 1930, 1933, 1936) and in various well-known 

 aerobic spore-forming bacteria (Badian, 1933, 1935; 

 Robinow, 1942). 



4. A single cell of Bact. coli or Proteus vulgaris 

 contains one chromatinic body or one or two pairs 

 of these, representing primary and secondary division 

 products. 



5. Few bacteria from young cultures are single cells. 

 When fixed through the agar with Bouin's mixture and 

 stained briefly with Giemsa's solution, bacteria from 

 young growing cultures of Bact. coli, Proteus vulgaris, 



B. mesentericus and B. megatherium assume a banded 

 appearance indicating that each bacterium consists of 

 two, three or four separate cells. 



6. A plasmolysing treatment has been applied to 

 B. megatherium which provides direct proof of the com- 

 posite structure of this bacillus by inducing its com- 

 ponent protoplasts to shrink away independently from 

 the outer supporting cell wall. 



I wish sincerely to thank Dr H. B. Fell for the hospi- 

 tality offered to me at the Strangeways Laboratory, for 

 her sustained interest in this investigation and for her 

 help in preparing the manuscript for the press. I have 

 also pleasure in admitting my indebtedness to Prof. 

 E. G. Pringsheim for much helpful criticism and advice 

 in matters relating to the bacterial cell wall. 



REFERENCES 



Badian, J. (1930). Acta Soc. Bot. Polon. 7, 55. 

 Badian, J. (1933). Acta Soc. Bot. Polon. 10, 361. 

 Badian, J. (1935). Acta Soc. Bot. Polon. 12, 69. 

 Badian, J. (1936). Acta Soc. Bot. Polon. 13, 105. 

 Badian, J. (1933). Arch. Mikrobiol. 4, 409. 

 Badian, J. (1937). Bull. int. Acad. Cracovie, B, 61. 

 Balint, A. (1926). Klin. Wschr. 5, 147. 

 de Bary, A. (1884). Vergleichende Morphologic und 



Biologie der Pilze, etc. Leipzig. English edition, 



Oxford, 1887. 

 Beebee, J. M. (1941). J. Bact. 42, 193. 

 Dobell, C. (1912). Arch. Protistenk. 26, 117. 

 Fischer, A. (1895). Jb. wiss. Bot. 27, 1. 

 Giemsa, G. (1912). Handbuch der pathogenen Protozoen, 



1. Leipzig. 

 Guiixiermond, A. (1908). Arch. Protistenk. 12, 1. 

 Gross, F. (1911). Mitt. Zool. Stat. Neapel, 2a, 188. 

 Klieneberger, E. (1934). J. Path. Bakt. 39, 409. 

 Klieneberger, E. (1942). J. Hyg., Camb., 42, 110. 

 Knaysi, G. (1930). J. Bact. 19, 113. 

 Knaysi, G. (1938). Bot. Rev. 4. 83-112. 



Knaysi, G. & Mudd, S. (1943). J. Bact. 45, 349. 



Knaysi, G. (1942). J. Bact. 42, 365. 



Lea, D. E. (1940). Nature, Lond., 146, 137. 



Lea, D. E., Haines, R. B. & Bretscher, E. (1941). 



J. Hyg., Camb., 41. 1. 

 Lea, D. E., Haines, R. B. & Coulson, C. A. (1937). 



Proc. Roy. Soc. B, 123, 1. 

 Migula, W. (1897). System d. Bakterien, 1. Jena. 

 Nakanishi, K. (1901). Zbl. Bakt. Abt. i, 30, !»7. 

 Neumann, F. (1941). Zbl. Bakt. Abt. n, Orig. 103, 



385. 

 Piekarski, G. (1937). Arch. Mikrobiol. 8, 428. 

 Piekarski, G. (1938). Zbl. Bakt. Abt. i, Orig. 142, 69. 

 Piekarski, G. (1939). Zbl. Bakt. Abt. i, Orig. 144, 



140. 

 Piekarski, G. (1940). Arch. Mikrobiol. 11, 460. 

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1, 1. 

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EXPLANATION OF PLATES 5- 



All figures on Plates 5 and 6, with the exception of 

 fig. 18, are of preparations fixed with osmium vapour, 

 treated with Njl HC1 at 60° C. and stained with Giemsa's 

 solution. Unless otherwise described, preparations were 

 photographed mounted in water. A scale of magnifica- 

 tion is provided on every plate and is the same for all 

 figures. 



Plate 5. Bacterium coli and Proteus vulgaris 



Figs. 1-9. Chromatinic structures in Bact. coli from five 

 nutrient agar plate cultures seeded with material from 

 18 hr./37°C. slant cultures and incubated for 45-90 min. 

 at 37° C. 



Fig. 1. a-h are successive stages in the development of 

 a coccoid element with a central pair of closely con- 

 tiguous chromatinic bodies into a typical rod-shaped 

 bacterium with four chromatinic structures, h may, 

 of course, also have arisen directly from a plump 

 bacillary form without having gone through the 

 coccoid stage. Note the V-shaped division stage at d. 



The dumbbell body forming the left limb of the V is 

 so much broader than the right one, that it seems 

 plausible to assume that it is preparing for the next 

 division. Compare this stage with PI. 7, fig. 26. 

 e a strand of chromatinic matter is seen connecting 

 recently separated chromatinic structures. Compare 

 with PI. 7, fig. 27. 



Figs. 2, 3. a-e successive developmental stages. The two 

 deeply stained dumbbell bodies at c are connected at 

 their base by a faintly stained round body similar to 

 that in /, fig. 1. Loss of clear-cut dumbbell shape 

 together with asymmetrical broadening of the chroma- 

 tinic bodies at d indicates impending division. The 

 same applies to the chromatinic structures in the 

 central bacterium in fig. 3. 



Fig. 4. Separation of the products of the 2nd division 

 of the chromatinic bodies is almost complete in the 

 right chromatinic structure in the central bacterium. 

 Stage d of Text-fig. 1 gives an interpretation of these 

 configurations suggested by thoir appearance under 

 the microscope at different levels of focus. 



180 



