CYTOLOGICAL CHANGES DURING GERMINATION 85 



strated in Figs. 1-4 on Plate I and, crudely simplified, in text Fig. 1. The 

 electron microscopy of sections of resting spores (Chapman, 1956, Robin- 

 ow, 1953) and the behaviour of the chromatin during and after its first 

 division (Robinow, 1956a, b) suggests that the second interpretation is the 

 correct one and that the chromatin structures lie directly in the cytoplasm 

 Avhich is for some reason at this stage always unduly basophilic. This is 

 clearly brought out by Figs. 2, 3 and 4, Plate I. In most of the spores in 

 these pictures there is a deeply stained matrix between and around the Feul- 

 gen-positive elements. In this instance the stain is Feulgen followed by 

 acetocarmine, but the same intense basophilia of the central region is also 

 seen in germinating spores that had been hydrolyzed and stained with Giem- 

 sa, although one would expect hydrolysis to have removed all but the nu- 

 clear basophilia. The material in question has not yet been characterized. 

 It disappears rapidly as growth of the young vegetative forms gets under 

 way. 



Perhaps these few remarks suffice to indicate that there are several mor- 

 phological problems of spore germination waiting to be solved by cyto- 

 chemistry and electron microscopy. 



(Also shown were photomicrographs illustrating the behaviour of the 

 chromatin during spore formation in B. megaterium, recently published else- 

 where [Robinow, 1956a] and a series of pictures of Metabacterium poly- 

 spora). 



References 



Chapman, G. 1956. Electron microscopy of ultra-thin sections of bacteria. 



II. Sporulation of Bacillus megaterium and Bacillus cereus. J. Bact. 71: 



348-355. 

 Fitz-James. P. C. 1953. The structure of spores as revealed by mechanical 



disruption. J. Bact., 66: 312-319. 

 Robinow. C. F. 1953. Spore structure as revealed by thin sections. J. Bact. 



66: 300-311. 

 Robinow, C. F. 1956a. The chromatin bodies of bacteria, pp. 181-214, in 



"Bacterial Anatomy." 6th Symposium Soc. Gen. Microbiol., Cambridge, 



1956. 

 Robinow, C. F. 1956b. The chromatin bodies of bacteria. Bact. Rev. 20, No. 



4. In press. 



Discussion 



P. C. Fitz-James 



I should like to begin this discussion by showing first some chemical data 

 whicU fit the pictures of germinating spores that Dr. Robinow has just 

 presented. 



Fig. 1 is taken from published material (Fitz-James, 1955) and shows 



