30 DR. E. KLEIN. 



parent and disintegrate, while the spores sink to the bottom 

 to form a minute precipitate. There is nothing of the sort in 

 our cultivations. As a general rule in the flasks and test- 

 tubes with fluid neutral pork broth no spore formation takes 

 place. Whether the cultivation is carried on at an ordinary 

 temperature or at a temperature of 20°— 25° or 32° — 35° C. 

 here is no spore formation. I have test-tubes with neutral, 

 pork broth in which exceptional spores have been formed 

 in the threads. These test-tubes were of the following 

 nature : in one test-tube an enormous mass of bacillus 

 threads had made its appearance while the cultivation was 

 kept in the incubator at 22° C. for about three weeks, the 

 masses of threads were very loose and consequently occupied a 

 large volume, so large that the growth extended almost to the 

 surface of the fluid; here numerous spores were found in the 

 superficial threads. Another test-tube of exactly the same 

 material inoculated with exactly the same generation of 

 Bacillus anthracis, and kept under precisely the same 

 conditions, did not develop any trace of spores ; here the mass 

 of bacillus threads formed a more dense growth, and kept its 

 place at the bottom of the test-tube far away from the surface 

 of the fluid. In another test-tube I found that the mass of 

 bacillus threads at first growing at the bottom of the fluid 

 after some time sent out some bundles of threads which grew 

 along the glass wall to the surface of the fluid. Here also 

 numerous spores were found in the threads. Buchner (1. c, 

 p. 370) says : " The physiological cause of the spore formation 

 lies in the commencing deficiency of nourishing material.^' 

 This is proved to be incorrect by our cultivation. The ex- 

 haustion of the nourishing fluid is long apparent and no spore 

 formation occurs, and vice versa, spore formation may be 

 observed long before there is any sign of exhaustion of the 

 nourishing matter, so much so that spores appear early in the 

 culture and again become converted into bacilli, but no spores 

 may be formed in this new generation. Pasteur says that he 

 prevents the formation of spores in the Bacillus anthracis 

 cultivated in chicken broth, by keeping the cultivation exposed 



