382 GLANDERS ANTHRAX PYOCYANEUS 



Immunity and Immunization. It is possible to immunize animals 

 both by the cautious injection of the bacilli which stimulate the for- 

 mation of specific bacteriolysins, and by filtrates of broth cultures of 

 the organisms, which incite the formation not only of bacteriolytic 

 substances, but antitoxic substances as well. No practical use is 

 made of these antibodies in human infections, however. 



Bacteriological Diagnosis. Wounds infected by Bacillus pyocyaneus 

 are usually diagnosed by the blue-green color of the dressings. The 

 bacilli are readily isolated upon gelatin plates, where the development 

 of the blue-green color is very characteristic. 



BACILLUS ABORTUS. 



Historical. Infectious abortion is a disease which has for many 

 years been recognized as an important economic one in the cattle 

 industry. Later it was found that the same disease also exists among 

 horses, goats and sheep. The organism was first isolated by Bang. 1 



Morphology. B. abortus is a small pleiomorphic bacillus, measuring 

 0.4 to 0.6 micron in diameter, by 0.6 to 2.5 microns in length. It 

 occurs singly and in pairs; rarely short chains of three to six elements 

 are found. The shape varies: some organisms are almost spherical, 

 others are distinctly rod-shaped, the latter being more frequently 

 found in broth cultures and in vivo. According to Priesz, 2 branched 

 forms may be found in older cultures. It is non-motile and possesses 

 no flagella, although Brownian movement may be fairly active. It 

 possesses no capsules, and no spores have been demonstrated. It 

 stains readily with ordinary anilin dyes, but somewhat irregularly, 

 some areas staining more intensely than others. Occasionally with 

 the methylene blue stain the organisms may present a bipolar appear- 

 ance. The organism is Gram-negative. 



Isolation and Culture. Initial growths on artificial media outside 

 the animal body are somewhat difficult to obtain. The organism 

 appears to grow best in a somewhat rarified atmosphere. This has 

 been obtained by Fabyan 3 by growing the organism on an agar slant 

 which is connected by a narrow tube with an agar slant on which 

 B. subtilis is growing. B. subtilis appears to so change the percentage 

 composition of the air in the two tubes that B. abortus grows fairly 

 readily. He also found that a pressure of three to five atmospheres 



1 Ztschr. f. Thiermedizin, 1897. i, 241 2 'S. 



2 Ccntralbl. f. Bakt., Orig., 1903, xxxiii. LJO 



3 Jour. Med. Research, 1912, xxvi, 441. 



