BACILLUS ANTHRACIS SYMPTOM ATICI 115 



leg and the quarter, accompanied with the formation of gases with a 

 strong odour, the following analysis being given by Kitt : Co 2 13 per 

 cent., H. 76 per cent., N. 10 per cent. On section of the affected 

 parts the muscles and cellular tissue are found saturated with bloody 

 serum, while the muscular tissue is dark, almost black, in colour. In 

 the affected areas, in the gall, and after death in the internal organs, 

 the above organism can always be detected. It is also found in the 

 soil in some localities. 



Microscopical Appearances. The bacilli are actively motile rods, 

 3 to 5 /x long, and 0'5 to 0'6 ^ thick, with rounded ends, usually 

 occurring singly, but sometimes forming short threads. The flagella are 

 attached around the periphery of the organism, peritricha (see Photo- 

 micrograph, Plate I., Fig. 4). The bacillus forms spores, situated either 

 in the middle or at the end of the rods (see Photomicrograph, Fig. 41). 

 The organism commences to grow at 16 to 18 C., but spore formation 

 takes place best at 37 C., and during this stage the organism becomes 

 motionless, being only motile during the vegetative stage. The organism 

 also undergoes degenerative changes, and involution forms are often 

 present, not only in cultures but in the tissues of affected animals. 



Staining Reactions. This organism stains by the ordinary aniline 

 dyes, and by the Gram method only when the staining process is 

 prolonged. It stains easily by the Cladius method. The spores can 

 also be stained by the ordinary methods (see Technique, p. 27). 



Biological Characters. The organism is . strictly anaerobic, 

 growing best in an atmosphere of hydogen, but not in carbon dioxide. 



On Gelatine Plates in an atmosphere of hydrogen the colonies appear 

 as irregular, slightly lobulated masses. The gelatine liquefies in a short 

 time, the colony then presenting a dark lobulated centre surrounded by 

 a delicate fringed-like zone. 



In Gelatine Stab Cultures a radiating cloudiness appears, which increases 

 in size as the gelatine softens, until finally the growth resembles a 

 caterpillar (see Photograph of Culture, Fig. 40), where the characteristics 

 of the growth correspond to those described by Sanfelice. 



In deep stab cultures in grape sugar agar-agar at 37 C. the growth 

 commences in twenty-four to forty-eight hours, accompanied by gas 

 formation, which is considerably more than is produced by the bacillus 

 of malignant oedema. The gaseous products have a putrid odour, like 

 that produced by rancid butter. 



Milk is coagulated by the formation of an acid. 



Differential Diagnosis. This organism is distinguished from the 

 bacillus of malignant oedema as follows : It is smaller and does not 

 develop in long threads in the animal tissues, is more actively motile, 

 and forms spores more readily in the living tissues than does the bacillus 



