22 MORPHOLOGY 



The fact that similar acid treatment does not destroy the chromatinic structures in 

 other types of cell, and that changes in the bodies are closely correlated with stages in 

 the growth of the cells, makes it highly unlikely that the dumbbell bodies are artefacts. 

 Robinow concludes that the chromatinic bodies are comparable with the chromosomes 

 of animal and plant cells. It may be noted that Beebe (1941) found single central Feulgen 



mm ^ ^^m 





B 



^t 



• 



C D 



Fig. 5. — Chromatinic bodies of bacteria, showing the various shapes taken during 



growth and division. 



A. B. mycoides, B. Bact. coli, C. Proteus vulgaris, D. B. mesentericus. (x 4,660). 



(From photographs kindly supplied by Dr. C. F. Robinow.) 



positive bodies in a myxococcus, which divided with the cell, and which at times developed 

 a dumbbell shape. 



The conception of the nuclear apparatus of bacteria as granules made up of one or 

 more chromosomes has been reviewed by Lindegren (1935). Lindegren himself (1936) 

 described a diploooccus whose nucleus, visible only at certain stages in division, consisted 

 of a single ha])loitl chromosome with seven chromomeres. Badian (1933) observed the 

 longitudinal division of a single rod-like chromosome in B. subtilis, and Chance (1938) 



