26 BACILLUS ANTHRACIS 



sent for examination, no trace of spore formation 

 can be seen. The chains of bacilli also are short, 

 unless the blood examined is that of a resistant 

 animal inoculated with a virulent culture, or that of 

 a susceptible animal inoculated with an attenuated 

 organism ; under these circumstances longer chains 

 of bacilli may be found. 



If a hanging drop bouillon culture be made from 

 the blood, and kept at 37° C, the individual cells 

 may be seen to divide and the resulting cells grow 

 until they resemble the original mother cells. As 

 the result of this division and growth the original 

 single cells or short chains develop into enormously 

 long, intertwisted, looped filaments, such as are 

 seen in Fig. 8. When unhampered in growth, the 

 chains of bacilli tend to arrange themselves with 

 remarkable parallelism. 



As the growth ages the division between the cells 

 becomes more marked and the cells more cubical. 

 At the same time, in the centres of many of the 

 cells highly refractile points appear, gradually in- 

 crease in size, and form an oval, highly refringent, 

 thick-walled body — the spore — which lies with its 

 long axis in the direction of the length of the cell 

 and does not cause any alteration in the cell form. 

 The protoplasm of the vegetative cell during this 



