ANTHRAX. 279 



and fade off as the lower part of the track is reached. After 

 a time the gelatine begins to liquefy, and slowly the feather- 

 like mass sinks to the bottom of the liquefied medium, 

 eventually forming an opaque white layer, which is found to 

 consist of bacilli in different stages of degeneration. The 

 upper layer of the gelatine, though perfectly clear, is now 

 quite fluid. This process of liquefaction comes on first along 

 the track of the needle, near the surface, and gradually 

 extends downwards until the whole needle track has dis- 

 appeared. We have then in the tube, the upper liquefied 

 gelatine, then the opaque layer of bacilli, and lastly the 

 clear solid gelatine below. If agar-agar be used in place 

 of gelatine, much the same appearances are presented ; 

 there is a smooth glistening greyish-white surface growth, 

 and the feathery rays appear to get more and more solid as 

 the growth continues, but no liquefaction takes place. On 

 solidified blood serum the colonies grow as greyish-white 

 layers on the surface, and the medium is very slowly liquefied. 

 On sterilized cooked potatoes the bacillus grows as a creamy- 

 white somewhat parchment-like granular mass, which rises 

 above the surface for some little distance but never extends 

 far in a lateral direction ; it has a peculiar dry appearance. 

 The growths on potatoes, as on other media, take place at 

 the ordinary temperature of the room. This organism can 

 be very readily inoculated into certain animals, with results 

 that may be looked upon as very definite ; for example, 

 if with a needle the point of which has been dipped into 

 the spleen of a cow that has died from anthrax a mouse be 

 pricked at the root of the tail, it will die in from seventeen 

 to eighteen hours, enormous numbers of bacilli being found 

 in its blood. It has been observed that in the case of some- 

 what larger animals, such as the guinea-pig, death does not 

 take place till a rather later period ; for instance, a guinea- 

 pig setoned with a silk thread containing spores of anthrax 

 bacillus will die on about the second or third day. If the 

 animal be examined after death, it will be found that near 

 the seat of inoculation there is usually very little to indicate 

 that this was the point at which the infective material was 

 introduced. Should, however, the inoculation be made into 

 the abdominal wall, there is usually marked cedematous 

 swelling of the peritoneum ; there may be small haemor- 

 rhages into the subcutaneous tissue, and there is usually 



