BACILLUS ANTHRACIS. 307 



1. Gelatin is liquefied. 



2. Milk is alkaline or very feebly acid in reaction, is 

 coagulated, and later the coagulurii is dissolved. 



3. All form little acid from grape-sugar (see Table I, at 

 end of the book, for quantitative statements) and no gas. 

 From milk-sugar there is formed little or no acid. 



4. No indol is formed. The production of H 2 S is 

 variable, never abundant. 



5. All are stained by Gram's method. 



The equipment with flagella appears also in this group 

 to be valuable for the diagnosis of species only with great 

 precautions. When present, they are peritrichous. 



Bacillus anthracis. F. Cohn and Koch. 



(Plates 34, 35, and 36.) 



Ordinary Names. Anthrax bacillus, Bacteridie du 

 charbon. 



Microscopic Appearance. In the animal body it 

 occurs as large vigorous rods, 3-10 p long, 11.2 /j. thick, 

 which are often arranged in longer or shorter chains (36, 

 i). The ends in fresh specimens are a little projecting 

 (rounded); after drying and staining, they appear square- 

 cut or slightly concave. To demonstrate the capsules, 

 which are always well developed in the animal body, fluid 

 blood-serum, and brain-agar mixture, the directions 

 given in the technical appendix are to be followed. Ac- 

 cording to Kern, capsules may be demonstrated in old 

 cultures upon most variable nutrient media. l 



In artificial nutrient media the bacilli grow into long 

 threads, placed parallel or somewhat twisted and en- 

 tangled (36, n), which either produce spores (see below) 

 or perish in the formation of bizarre involution forms 

 (36, v). The threads, even when unstained, give indi- 

 cations of their being composed of separate bacilli (36, 

 vi ). This is especially distinct after staining. 



1 Noetzel has also demonstrated capsules in undoubted "cadaver 

 bacilli," and this points out how unsafe it is to allow the diagnosis of 

 anthrax to rest upon the demonstration of capsules, which is often 

 very much overestimated by veterinarians. (C. B. XIX, 498.) 



