40 DR. E. KLETN. 



and the subdivision of the protoplasm into square or rather 

 cubical individuals or cells. Adding a nearly concentrated 

 solution of acetate of potash to the fresh preparation brings 

 out these appearances also very well. Still more, and in fact 

 with marvellous distinctness, does it come out in dried and 

 stained specimens (after Weigert and Koch). Watching the 

 bacilli of the spleen or any other organ while drying under the 

 microscope, the gradual differentiation into sheath and cubical 

 cells can be followed very readily. I have made an endless 

 number of stained specimens of bacillus threads of my cultiva- 

 tions in pork broth and gelatine pork, and have invariably 

 found the same appearances, provided the specimens be not 

 overstained, or if so, well washed with alcohol, viz. the whole 

 protoplasm of each thread is subdivided into a single row of 

 cubical cells, stains well with the anilin dye, and distinct from 

 the general sheath of the thread. Koch has pointed out that 

 the Bacillus anthracis shows in dried and stained speci- 

 mens a very characteristic subdivision into shorter or longer 

 rod-like structures, and by this alone Bacillus anthracis 

 can be distinguished from other bacilli. He gives in his work 

 (' Cohn's Beitrage II,' Bnd. iii) a photograph to illustrate this 

 point. In this illustration the subdivision of the protoplasm 

 is not by any means numerous, far less than in my case, for I 

 find the individual members not rod-shaped but cubical. It is 

 true here and there it is seen that instead of a cubical we have 

 an elongated or rod-shaped cell, but in some of these we can 

 clearly discover a slight constriction in the middle, a sign of 

 commencing division into two. The independence of the 

 common sheath of the thread and these cells Koeh has not 

 noticed. 



But also in the bacilli of the blood and spleen of mice, 

 guinea-pigs, and rabbits, dead of anthrax, I have noticed pre- 

 cisely the same distinction into common sheath and the sub- 

 division of the protoplasm into cubical cells, or when the cells 

 are elongated a middle constriction was noticeable. Accord- 

 ingly the length of a bacillus, viz. whether a longer or shorter 

 rod or a longer or shorter thread, depends entirely on the 



