16 



W. NIKLOWITZ 



Fig. 1. Electron micrograph of an ultra-thin longitudinal 

 section from Escherichia coli (three hours culture). Magnifi- 

 cation 90,000. 



scopic investigations, reveal a structure deviating 

 from that of higher organisms. In our opinion the 

 idea drawn from what was seen in uUrathin sections 

 and light-microscopical investigations, i.e. that bac- 

 teria contain true nuclei with chromosomes, is pre- 

 mature, especially when taking into consideration 

 that even the results concerning the fine structure of 

 chromosomes in higher organisms are still rather 

 incomplete. Moreover, comprehensive studies of 

 fixed series of different stages of the development 

 revealed that the image will largely depend upon 

 the fixation. According to Geitler (9), emphasis 

 should not rest on the alternative question nucleus 

 or no nucleus, chromosomes or no chromosomes, 

 but on exactly hitting upon the equivalents of the 

 nucleus. 



From our investigations the following procedure 

 has proved most favourable for the fixation. The 

 objects — whether prefixed (2, 11) or not — are fixed 

 in a puffered solution of OsO^ (pH 6.8; 7.1; 7.4), 



added with 0.2 Af saccharose for 10-15 min. at 4'C. 

 This fixation is followed by a further one in formol 

 (1:10) for 4-6 hours. 



This procedure avoids an unfavourably long expo- 

 sure to OsOj, as well as the addition of NaCl (3). 

 As has earlier been stated ( 1 ), a prolonged fixation 

 with OsOj causes a destruction of the tissues, and 

 the addition or a washing with NaCI entails an 

 enormous loss of substances (22). 



Fig. I represents a section through Escherichia 

 coli. The substructure of the cytoplasm is granular. 

 In the central bright region filamentous elements 

 with a mean thickness of 80 A may be recognized. 



From our investigations it became evident that 

 the distribution and the diameter of these filaments 

 will vary with different fixations. 



This short report at this Conference was intended 

 to demonstrate that our ultramicrotome renders 

 possible to do routine sections which are suitable 

 for carrying out submicroscopic studies, and 1 should 

 like to conclude my arguments citing a sentence of 

 the nestor in the field of investigation of submicro- 

 scopic structures, Frey-Wyssling, who states that just 

 as classical physiology reached its present summit 

 only following the perfection of histology, the pro- 

 gress in physiology of the cell will depend upon 

 shedding more light on the submicroscopic morpho- 

 logy of the cell. 



References 



1. Bahr, G. F., Exptl. Cell Research 9, 277 (1955). 



2. Birch-Andersen, A., Maaloe, O., and Sjostrand, F.S., 



Biochim. et Biophys. Acta 12, 395 (1953). 



3. Chapman, C. B. and Hillier, J., /. Bacterial. 66, 362 



(1953). 



4. Drews, G. and Niklowitz, W., Arch. Mikrobiol. 24, 



147 (1956). 



5. — ibid. 25, 333 (1956). 



6. Ekholm, R. andZELANDER,T., EATJe/vV/fZ/rt 12, 195(1956). 



7. Frey-Wyssling, A., Protoplasntatologia 2, A/2 (1955). 



8. Gansler, Ft., Vortrag auf der 6. Tagung der Deutschen 



Gesellschaft fiir Elektronenmikroskopie, Miinster 

 1955. 



9. Geitler, L., Fortschr. Bat. 17, 1 (1955). 



10. GiUNTiNi, J. and Edlinger, E., Ann. Inst. Pasteui 86,671 



(1954). 

 1 1. Kellenberger, E. and Ryter, A., Schweiz.Z. Pathol, u. 



Bakteriol. 18, 1122 (1955). 



12. KiESER, H., Arch.Geschwulstforsch. (1957, in press). 



13. Knoll, H. Zeifl-Nachrichten 5, 38 (1944). 



14. Knoll, H. andZAPF, K.,Zentr. Bakteriol. Parasitenk., 



Abt. I Orig. 157, 389 (1951). 



15. — ibid. 161, 241 (1954). 



16. Niklowitz, W., Mikroskopie, Wien, 10, 401 (1955). 



17. Niklowitz, W. and Drews, G., Arch. Mikrobiol. 23, 



123 (1955). 



18. — ibid. 24, 134 (1956). 



19. — ibid. (1957. in press). 



20. SiTTE, H., Mikroskopie, Wien, 10, 365 (1955). 



21. Sjostrand, F. S. and Rhodin, J., E.xpil. Cell Research 



4, 426 (1953). 



22. Sylven, B., Acta Union Intern, contre le Cancer 7, 708 



(1951). 



