154 MICRO-ORGANISMS AND DISEASE. [CHAP. 



scopic observation that the bacillus anthracis, at first non-motile, 

 is capable of becoming motile. At one or both ends a flagellum 

 grows out from its body. But this observation is unreliable, 

 since Ewart did not guard himself in any way from the acci- 

 dental introduction of septic bacilli, many of which are motile. 

 Besides, he says of the bacilli, which he figures as anthrax 

 bacilli, that they are connected with one another by two fine 

 threads, and that they probably separate from one another and 

 each retains one filament, which is its flagellum. But his 

 observations, so far as they have application to anthrax bacilli, 

 are capable of quite a different interpretation. In every 

 specimen of blood and in every artificial culture bacilli can 

 be seen, in which at one place or more the protoplasm is 

 wanting, owing as I have shown, to degeneration ; in such 

 places only the empty sheath is present, and of course in fresh 

 specimens this gives the appearance as if the two protoplasmic 

 portions of the bacillus were connected with one another by 

 two fine threads, i.e. the sheath being transparent is seen here 

 edgeways. 



In no instance has the bacillus anthracis been observed to be 

 motile. I have examined thousands of specimens of fresh 

 bacillus anthracis in the blood and in artificial cultures, and I 

 have never seen anything that in the least would lead me to 

 differ from this proposition. 



As regards the spores they are of the same aspect and size in 

 both the hay bacillus and bacillus anthracis. The threads in 

 good cultures form in both cases the same bundles more or less 

 twisted and forming convolutions, but in certain cultures of the 

 bacillus anthracis, e.g. in broth, in which the growth is limited 

 to the bottom of the fluid, the convolutions and the twisted 

 condition of the threads are more pronounced, more cable- 

 like. 



Hay bacillus being motile, every culture of it is uniformly 

 turbid, the bacilli being capable of moving about, and after a 

 day or two of incubation at 35 C. they form a distinct pellicle 

 on the surface of the fluid, which in further stages becomes 

 complete and thick. These pellicles are composed of a dense 

 feltwork of threads of the bacilli, and in them spore-formation 

 is going on. 



By shaking the fluid the pellicle sinks to the bottom, and if 

 the fluid is not exhausted yet, a new pellicle is formed of the 

 same nature. 



In no culture of hay bacillus are there ever observed those 

 cloudy, fluffy, whitish and transparent convolutions that are 

 seen in cultivations of bacillus anthracis carried on at the 



