ANTHRAX. 273 



. 



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, 

 and that the envelope is used up during its 

 growth. 



At 35 C. (95 Fahr.) spores make their ap- 

 pearance at the end of twenty-four hours. At a 

 lower temperature (28 C.) the growth of the rods 

 into filaments takes place more slowly, and the 

 formation of spores is not completed in less than 

 thirty-six to forty-eight hours. At 42 to 43 C. 

 the rods grow and multiply by fission, but spores 

 are no longer formed. No development occurs 

 at temperatures below 12 C. (53.6 Fahr.). In 

 Fig. 3, Plate XL, a spore-bearing filament is seen 

 in the centre of the field, while scattered about 

 are liberated spores and detached segments of the 

 filaments. The amplification is 500 diameters, 

 and the specimen is from a culture made in 

 chicken bouillon. 



A statement relating to the source of the ma- 

 terial which furnished specimens for my photo- 

 micrographs, Figs. 1, 2, and 3, Plate XL, may not 

 be uninteresting as illustrating the facts already 

 given. 



While pursuing certain experimental inquiries 

 in the biological laboratory of Johns Hopkins 

 University during the summer of 1881, Professor 

 Martin placed in my hands a small tube just re- 

 ceived by him from Dr. Burdon-Sanderson, of 



18 



