ANTHRAX. 273 



then separated, and one of them is at once lowered on to a 

 drop of three-quarter per cent, salt solution, the other being 

 set aside to dry, after which it may be gently heated in the 

 flame of a spirit lamp and then stained in a water solution 

 of methylene blue, well washed in water and alcohol, and 

 mounted in a drop of water or glycerine. In the unstained 

 specimen there will be found lying between the red blood cor- 

 puscles a number of short rods of the size above mentioned, 

 each of which has slightly rounded ends ; sometimes also 

 there may be seen a delicate transverse mark running across 

 the middle, this being especially well marked when the rods 

 are longer than usual. The centre of each rod in the stained 

 specimen appears to be quite homogeneous, and is usually 

 deeply stained ; around this deeply stained portion is a kind 

 of sheath which remains unstained, or is only slightly tinged 

 by the colouring reagent. In some cases there is also at the 

 point of junction, on each side of the transverse line, a some- 

 what oval area slightly stained, so that when a number of 

 these rods are placed end to end without being separated 

 they have very much the appearance of a finger with the 

 joints slightly enlarged, or of a bamboo cane with its charac- 

 teristic thickenings placed at almost regular intervals. Both 

 rods and threads are perfectly motionless. In other cases, in 

 place of a mere transverse line, there is the appearance pre- 

 sented of two bacilli that have only recently become separated 

 from one another, still close together, however, and often so dis- 

 posed that they enclose an angle. In the coloured prepara- 

 tion the same thing is observed. It is now seen that where 

 the rods obtain any considerable length they are distinctly 

 segmented, each chain being divided into a number of short 

 rods, and at regular intervals at the points of segmenta- 

 tion there is usually a slight swelling, although as yet there 

 is no trace or evidence of any spore formation. 



In cases of wool-sorters' disease, which is very frequently 

 accompanied by pleurisy, these organisms may be found in 

 the fluid that accumulates in the chest as long threads, 

 which may be grouped together in a kind of network or 

 felt, the individual threads of the bundles often reaching 

 an enormous length without there being any appearance 01 

 segmentation. 



A similar growth of long threads has also been obtained by 

 cultivating the bacilli, from the blood of the guinea-pig 



19 



