ANTHRAX. 271 



the blood loses its virulence, and neither rods nor 

 spores can be discovered in it after a few days. 



According to Ewart, when cultivated upon a 

 warm stage in albuminous fluids, the anthrax rods 

 become motile within a few hours, and exhibit al- 

 ternations of motion and quiescence. This does 

 not correspond with the observations of Koch, and 

 is probably a mistake. Magnin, on page 88 of the 

 present volume, in giving the specific characters 

 of B. anthracis, states that it is always motionless. 

 If the temperature is maintained at about 33 C. 

 (91.4 Fahr.) the rods soon grow into long homo- 

 geneous filaments, which in the course of four or 

 five hours may reach a length many times greater 

 (50-100 times) than the original bacilli. These 

 are often twisted and interlaced in the culture- 

 fluid. A little later the filaments, which were at 

 first hyaline, are seen to consist of a distinct 

 sheath and a central cylinder of protoplasm, which 

 soon undergoes segmentation, each segment being 

 about the length of the original rods. The spores 

 are formed by a consolidation of the protoplasm 

 of one of these segments into an oval mass, which 

 is subsequently set free by rupture of the cellular 

 envelope, or by its granular disintegration. The 

 oval shining spores after their escape present the 

 appearance of being enclosed in a gelatinous en- 

 velope, which according to Koch, is developed 

 into a new rod when germination takes place. 

 Other observers (Ewart, Cohn) assert that the 

 central protoplasm is developed into a new rod, 



