LIVING SUBSTANCE 



67 



original Monera is constantly diminishing, and the few that 

 cannot yet be obtained for fresh investigation are now also 

 regarded by most investigators as nucleated cells in which the 

 earlier incomplete technique was not able to demonstrate nuclei, 

 just as was the case with the others that are now recognised as 

 nucleated. 



The Bacteria have defied much longer than the Monera attempts 

 to find in them a differentiation corresponding to the nucleus and 

 protoplasm of other cells. All imaginable methods of staining 

 and the strongest microscopic 

 powers were not able to demon- 

 strate the two different kinds 

 of living substance within their 

 minute and apparently com- 

 pletely homogeneous bodies. 

 This state of our knowledge 

 continued until a very few 

 years ago, in spite of the great 

 advance that bacteriology made. 

 Recently, however, Biitschli 

 ('90) succeeded in discovering 

 a fine structure in the bodies 

 of Bacteria. He found that by 

 the use of very strong magni- 

 fying powers and not too strong 

 illumination certain specific 

 staining-reagents, which, as, 

 e.g., hsematoxylin, colour only 

 the nuclear substance and not 

 the protoplasm, make visible 

 two different substances in the 

 bodies of Bacteria ; one of 



these is stained intensely, the other not at all. The quantitative 

 relations of the two substances are characteristic : the volume 

 of the stained substance is usually greater than that of the un- 

 stained, but the relative arrangement of the two is different in 

 different species. In one species, as, e.g.. Bacterium lineola (Fig. 

 9, a), the stained substance lies in the middle, and the unstained 

 substance forms a delicate peripheral layer about it; in others, 

 especially the corkscrew-like forms of Spirillum, such as Spirillum 

 undula (Fig. 9, b), which is common in stagnant water, the un- 

 stained substance is accumulated at one end or both ends of 

 the elongated body, and the latter consists otherwise wholly of 

 stained substance. This differentiation jof the body-substance into 

 two portions, one of which is stained and the other unstained by 

 specific staining-reagents, appears to correspond entirely to the 

 division of the living substance into nucleus and protoplasm that 



F 2 



FIG. 8.Pelomyxa pallida. A rhizopod contain- 

 ing very finely-divided nuclear substance 

 Gruber.) 



