6 BACTERIOLOGY. ' 



so-called paraplastic granules of an oily or of a 

 starchy character, grains of sulphur, and at 

 times vacuoles. The cell-membrane has been 

 long known and the fact of its existence se- 

 curely established. It consists in some in- 

 stances of a substance physically altered, but 

 akin to protoplasm, and is of a proteid nature, 

 thereby resembling the membrane of animal 

 cells. Some species, however, possess a cellu- 

 lose-like membrane resembling that of the 

 typical plant cell. 



Many years ago I was able to show that dur- 

 ing the division of bacteria there occurred a 

 very remarkable arrangement of the granules 

 made visible by staining, which is similar to 

 that taking place in the division of the nu- 

 clear filaments of higher cells. The manner in 

 which the general bacterial substance stains is 

 also suggestive of nuclear and not of cytoplas- 

 mic reaction. Biitschli l definitely conceives the 

 whole central part of the cell to be the nucleus ; 

 according to this conception, the smallest bac- 

 teria would possess hardly more than a mantle 

 of cytoplasm and often would consist entirely of 

 nuclear substance. More often it is possible to 

 detect the presence of granules which react like 

 nuclear substance, and which must, therefore, 



1 Cf. Weitere Ausfuhrungen iiber den Bau der Cyanophyceen und 

 Bakterien, Leipzig, 1896. 



