BACTERIA AND DISEASE 303 



toplasm of the bacillus becomes granular; the granules 

 coalesce, and we have spores. Each spore possesses a thick 

 capsule, which enables it to resist many physical conditions 

 which kill the bacillus. When the spore is ripe or has ex- 

 hausted the parent bacillus, it may take on a resting stage, 

 or under favourable circumstances commence germination, 

 very much after the manner of a seed. The spores may in- 

 fect a farm for many months; indeed, cases are on record 

 which appear to prove that the disease on a farm in the 

 autumn may by means of the spores be carried on by the 

 hay of the following summer into a second winter. Thus, 

 by means of the spores, the infection of anthrax may cling 

 to the land for very long periods, even for years. Spores 

 of anthrax can withstand 5 percent, carbolic acid or i-iooo 

 corrosive sublimate for more than an hour; even boiling 

 does not kill them at once, whilst the bacilli without their 

 spores are killed at 54 C. in ten minutes. When the spores 

 are dry they are much more resistant than when moist. 

 Hence the persistence of the anthrax bacillus is due to its 

 spores. 



The bacillus is aerobic, non-motile, and liquefying. Broth 

 cultures become turbid in thirty-six hours, with nebulous 

 masses of threads matted together. The pellicle which 

 forms on the surface affords an ideal place for spore form- 

 ation. 



Cultures in the depth of gelatine show a most character- 

 istic growth. From the line of inoculation delicate threads 

 and fibrillae extend outwards horizontally into the medium. 

 Liquefaction commences at the top, and eventually extends 

 throughout the tube. On gelatine plates small colonies 

 appear in thirty-six hours, and on the second or third day 

 they look, under a low power of the microscope, like matted 

 hair. The colonies after a time sink in the gelatine, owing 

 to liquefaction. On potato, agar, and blood serum anthrax 

 grows well. 



