BACILLUS ANTHRACIS. 237 



the head of a medusa. Ultimately individual threads, 

 or bundles of threads, hranch off from the irregular 

 periphery, and grow over the gelatine in various direc- 

 tions. At the same time the gelatine is liquefied over 

 a small area ; the colonies, which have now a diameter 

 of 2 to 4 mm., hegin to float and break down at their 

 margins under the action of the fluid formed. In punc- Puncture 

 ture cultivations in gelatine a delicate whitish line is Cl 

 formed along the needle track, from which fine threads 

 run off at right angles, and grow in a ray-like form into 

 the jelly, extending furthest on and near the surface, to 

 a less extent at the deeper parts of the puncture ; here 

 also slow liquefaction begins after two or three days, in 

 such a way that the radiating branches at first remain, 

 and it is only in the course of eight days that the 

 colonies sink to the bottom of the liquefied area, which is 

 now more extensive. On the addition of a small quantity 

 of agar to the nutrient jelly, no liquefaction occurs. On Growth on 

 slices of boiled potatoes the anthrax bacilli form greyish- J 

 white elevated gelatinous deposits with a rough surface; 

 these deposits do not extend over the whole surface of 

 the potatoes, but only spread for 3 to 5 mm. from the 

 line of inoculation. On blood serum they form whitish 

 layers ; in meat infusion they cause a cloudy turbidity, 

 which develops by preference at the bottom of the 

 vessel. 



When introduced even in minimal quantities into the Action on 

 blood of living animals or man by intravenous injection JJ^J flals and 

 or subcutaneously, the bacilli cause anthrax, which either 

 takes the form of local symptoms, anthrax carbuncles, 

 and then not uncommonly ends in recovery, or appears 

 as a septicaamia, and then usually rapidly ends in death. 

 Anthrax was the first case in which an infective disease 

 occurring in man was proved with certainty to be due to 

 a vegetable micro-parasite, the organism being at the 

 same time inoculable on various animals, and being thus 

 suitable for experimental study. The smallest trace of 

 a cultivation of anthrax bacilli inoculated on mice, 

 rabbits, guinea-pigs, hedgehogs, sparrows, sheep, and 

 horses, causes the illness or death of the animals from 



