28 DR. E. KLEIN. 



tions, i.e. whether pure or not, as is the case in most culti- 

 vations of bacteria, except, perhaps, of Bacillus anthracis, 

 I have employed both methods, i.e. I cultivated it in the test- 

 tube or flask, and at the same time controlled it under the 

 microscope, by cultivating in the above glass cell a specimen 

 in a drop of solid gelatine nourishing material. 



In the cultivations of Bacillus anthracis in the above- 

 named neutral pork broth in test-tubes or small or large flasks 

 with which I worked, after three or four or more days' incuba- 

 tion, even at a temperature so low as 20° to 25° C, a beautiful 

 whitish crop of the bacilli is visible at the bottom of the 

 vessel in the shape of a fluff'y, nebulous, more or less filamen- 

 tous mass as incubation proceeds, gradually extending into the 

 further layers of the fluid, this latter being tolerably bright 

 and limpid. These appearances have been well described by 

 Pasteur, and have been also noticed by Buchner (I.e. p. 376). 

 The cultivations which I carried on in the pork broth, from 

 one transfer to the other, all showed these characteristic appear- 

 ances, except in those few instances in which, as mentioned 

 above, an accidental contamination occurred. These appear- 

 ances are so striking and peculiar that it can with certainty, 

 from the naked-eye inspection alone, be recognised whether a 

 given cultivation is one of pure anthrax.^ If the growth after 

 the first few days does not present the peculiar nebulous and 

 filamentous masses at the bottom of the fluid, if the super- 

 natant fluid remains clouded and turbid, and especially if a 

 scum appears on the surface, either only where the surface of 

 the fluid adheres to the glass or over the whole surface, it can 

 be concluded with probability that the cultivation is impure, 

 there being generally present a microccocus or a scum-forming 

 bacterium or a bacillus, and this can be easily verifiedjby micro- 

 scopic examination. ])uring the first two or three days of 

 incubation, however, the fluid is not limpid, but more or less 



1 These appearances are much more striking in neutral cultivations than in 

 those of acid or alkaline reaction. In the latter instances there is never the 

 same copious growth as in the first. 



