ANTHRAX. 457 



oxygen upon the surfaces of the culture-media. When a 

 spore is placed under favorable conditions for its devel- 

 opment and is carefully watched, it may be observed to 

 increase in length a trifle, then to undergo a rupture at 

 one end, from which the new bacillus projects. The 

 spores of anthrax (Fig. 107), being large and easily ob- 









FlG. 107. — Bacillus anthracis, stained to show the spores; x icoo (Tr'ankel 



and Pfeiffer). 



tainable, are excellent subjects for the study of sporula- 

 tion, for the action of germicides and antiseptics, and for 

 demonstration by stains. When dried upon threads of 

 silk they will retain their vitality for several years, and 

 are highly resistant to heat and disinfectants. 



Spores of anthrax are killed by five minutes' exposure 

 to a temperature of ioo° C. It is said by some that 

 spores subjected to 5 per cent, carbolic acid can germinate 

 when introduced into susceptible animals, their resist- 

 ance to this strength carbolic solution being so remarkable 

 that they are not usually destroyed by it under twenty- 

 four hours. Spores are also killed in a short time by- 

 exposure to 1 : 1000 bichlorid-of-mercury solution. 



The bacilli are not motile and are not provided with 

 flagella. They stain well with ordinary solutions of the 



