OTHER INTRACELLULAR GRANULES 23 



a mitosis-like effect during the division of a bacillus resembling B. mesentericus. Prior 

 to sporulation, the chromosomes of Badian's bacillus underwent division, followed by 

 fusion end-to-end of the resulting two chromosomes, and division of the fused chromosome 

 into four, only one of which was incorporated in the spore. A similar series of events 

 was observed by Allen, Appleby and Wolf (1939) in a spore-bearing bacUlus. The normal 

 vegetative cell contained one haploid chromosome. Two kinds of spore were formed, 

 one haploid, the other diploid. In the one case a phenomenon analogous with meiosis 

 occurred before spore formation, in the other after spore germination. 



A nucleoprotein granule which persisted in aU stages of growth, multiplication, ageing 

 and starvation of the culture, and which divided before cell division, was found in a 

 staphylococcus by Knaysi (1942). The granule did not correspond to any known cellular 

 reserve material, and was apparently the nuclear apparatus. 



Taking the evidence as a vv^hole, it appears that bacteria have a nuclear apparatus 

 which in many respects is analogous to that of the cells of fungi, plants and animals, 

 though the survey of bacteria by modern cytological methods is as yet too limited 

 to permit more than a tentative conclusion that the apparatus seen in a few bacteria 

 will prove characteristic of bacteria in general. 



Other Intracellular Granules. 



Nitrogenous Material — Volutin Granules.- — In many species of bacteria there 

 are found intracellular granules which possess a strong affinity for nuclear stains, 

 and which are coloured a reddish purple with certain blue or violet stains, especially 

 with polychrome methylene blue. These granules were first described by Ernst 

 (1888, 1889, 1902) and by Babes (1889, 1895), and are frequently referred to as 

 the Babes-Ernst granules. They have also been named volutin granules, and 

 from their peculiar staining properties, metachromatic granules. These con- 

 stituents of the bacterial cell have, from time to time, been credited with almost 

 every conceivable function. There is now, however, very general agreement that 

 they are relatively inert in the cell. Using a cytological term, they are meta- 

 plasmatic granules, particles of some substance concerned in cell-metabolism. 

 Their number and size vary according to the medium in which the bacterium 

 is grown, and according to the period of growth. That they form no part of 

 the nuclear apparatus is shown by the facts that they can be observed in yeasts 

 and fungi, which possess well-differentiated nuclei, and that they take no active 

 part in cell-division or sporulation. They contain a high proportion of nucleo- 

 protein, and to this they probably owe their affinity for nuclear stains. 



The role which they play in the chemistry of the bacterial cell is at present 

 unknown ; the suggestion of Marx and Woithe (1900), that the presence of these 

 granules is correlated with the virulence of the bacterium, has been completely 

 disproved by the work of several subsequent investigators (Ascoli 1901, Krompecher 

 1901, Gauss 1902, Ficker 1903, Guilliermond 1906). Groh (1938) has recently 

 assigned a reproductive role to the volutin granules of C. dipJitherice. His findings 

 still await confirmation. 



Carbohydrates. — Glycogen granules and starch granules occur in many species 

 of bacteria, and may be identified by staining with iodine. 



Fats and Lipoids. — Fat globules are frequently found in bacterial cells, and 

 may be stained by the usual fat-soluble dyes. Other lipoidal or waxy substances, 

 which may be extracted by the usual solvents, are found in many bacteria, and 

 are particularly abundant in certain species, such as the acid-fast bacilli. 



These different forms of granular products of metabolism are by no means 

 equally abundant in different bacterial species. In some, volutin granules tend 



