SEX IN BACTERIA— FAIDENCF. FROM iMORPHOLOGY 39 



qucncc of cliangcs must he inferred by logic and analogy rather than 

 demonstrated by direct observation. 



\Mien a film of fixed and stained cells is examined microscopi- 

 cally, one sees in each cell only one manifestation of the manifold 

 morphological transformations of which the organism may be capa- 

 ble. All the different stages may or may not be present in the same 

 film. Unless the behavior of living cells under as nearly the same 

 environmental conditions as possible is also studied microscopically, 

 tlie sequence of the stages is left to the imagination of the investigator. 



Unfortunately, the bacteriologist with present-day methods is 

 definitely limited in the amount of detail which he can resolve in the 

 living cell. Therefore, fixed and stained cells must still be heavily 

 relied upon particularly for the differentiation of minute internal de- 

 tail. This, however, is no reason wdiy one should confine all morpho- 

 logical studies to dead cells when the behavior of cells as units in such 

 phenomena as ceil fusion and conjugation could be examined in the 

 living condition by the phase contrast microscope, an instrument well 

 adapted to the study of gross morphology of bacteria. By what better 

 way, techniques permitting, can one determine the behavior of indi- 

 vidual cells in a culture than by observing and photographing in 

 natural sequence the activities of these cells as they are actually per- 

 formed? 



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1953. Do bacteria have mitotic spindles, fusion tubes and mitochondria? 



/. Gen. Microbiol., 8, 50-57. 

 Braun, A. C, and R. P. Elrod. 1946. Stages in the life history of Phytoiiwnas 



twiiefacievs. J. Bact., 52, 695-702. 

 Cassel, W. A. 1951. Apparent fusion of the chromatinic bodies in species of 



Bacillus. J. Bact., 62, 514-515. 

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Spring Harbor Symposia Quant. Biol., 16, 381-412. 

 DeLamater, E. D., and M. E. Hunter. 1952. The nuclear cvtology of sporula- 



tion in Bacillus viegateriwn. J. Bact., 63, 13-21. 

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bacillus nioniliforTiiis. Proc. Soc. Exptl. Biol. Med., 53, 84-86. 



