200 TEXT-BOOK OF BACTERIOLOGY. 



great number of very small grains and dots, which are irregularly 

 distributed over the bacterial body and which appear sometimes 

 quite dark and opaque, sometimes with a gleam peculiarly their 

 own. 



Twelve hours more, and the picture is once more transformed. 

 The number of threads has still further increased ; they now fill the 

 whole preparation in dense masses and generally show an arrange- 

 ment which is characteristic of the anthrax bacillus. They twist 

 in numerous windings round each other, and thus sometimes form 

 very remarkable groups which might remind one of the appearance 

 of a Chinaman's pigtail, or a ship's cable with the twisted threads 

 that compose it. 



The granulation has in the mean time become more distinct, an^ 

 now at a suitable temperature usually develops into spore-formation. 

 The small aggregations of more solid protoplasm flow gradually 

 toward the middle of the cell and unite there to form a large, 

 strongly-refracting body, which gleams forth out of a darker back- 

 ground as a bright spot with somewhat irregular boundaries. This 

 body increases in brilliancy, its form becomes well defined, it be- 

 comes surrounded with a capsule, which may be recognized as a 

 sharp contour, and the spore is now fully formed. The fruit-bear- 

 ing cell has not altered its appearance during this process, and the 

 spore lies, an egg-shaped, bright, shining thing, in the middle of 

 the cell, than which it is considerablj' shorter, although about 

 equallj' broad. If the sporulation extends at the same time to all 

 the members of a thread, it yields a particularly beautiful sight. 

 Like pearls on a string, the gleaming little balls lie at regular dis- 

 tances from each other. 



Presently the transparent remainder of the cell-contents which 

 was not employed to form the spore dissolves and vanishes — the 

 spore is free. 



If the latter finds its way into fresh nutritive solutions, it begins 

 to sprout and becomes a rod-cell. In order to watch this precess 

 under the microscope the spores should be transferred into a hang- 

 ing drop of nutrient gelatin, or still better, food agar. The drop 

 quickly hardens and imbeds the separate spores which it contains 

 so firmly that they cannot get away from the spot, and can thus 

 be subjected to an uninterrupted examination. We then see that 

 the spore begins to lose its gleam, stretches itself longitudinally 

 till the tough spore membrane breaks at one pole, and the young 

 rod-cell makes its appearance at the opening. It stretches itself in 

 the direction of the longitudinal axis of the spore, pushes off the 

 membrane completely, and so brings the simple course of develop- 



