BACILLUS TUBERCULOSIS AND ALLIED ORGANISMS 12$ 



Properties. They are not motile; do not produce gas; 

 some pigment on potato. 



Growth. The growth occurs between 25 and 40 C. best 

 at 37 C.; it is very sparse upon gelatin, but on glycerin-agar 

 or blood-serum a very abundant growth occurs. Easily de- 

 stroyed by heat, but cultures sealed and protected from 

 light may live several months. 



Colonies. On agar or glycerin-agar there appear in two to 

 three days small white glistening drops, which under micro- 

 scope seem as round granular masses with an even periphery, 

 similar to young B. typhi colonies. 



Stroke Cultures. On glycerin-agar and blood-serum small 

 transparent drops of whitish or grayish color, which soon 

 coalesce to form a broad band like B. coll. 



Potato. An amber-colored, honey-like growth which grad- 

 ually turns red, then brown, and greenish-brown around it. 

 Weakly acid potatoes are a good medium and give the most 

 typical growth. 



Staining. Gram negative. Since the bacillus is very easily 

 decolorized, some special methods have been recommended. 

 Loffler's and Klihne's solutions for cover-glass and sections. 

 (See Staining.) 



Pathogenesis. If horses, field-mice, or guinea-pigs be inocu- 

 lated subcutaneously with but a very small quantity of cul- 

 ture, a local affection results, followed some time after by 

 a general disturbance; ulcers form at the point of inocula- 

 tion little nodules, which then caseate, leaving scars and 

 involving the lymphatics; metastatic abscesses then occur in 

 the spleen and lungs, and death from exhaustion. Cattle, 

 pigs, and rabbits are not easily affected; man is readily 

 attacked. The bacilli gain entrance to the blood and urine. 

 Nasal glanders occurs whatever the mode of inoculation. In 

 the horse the type is more chronic than in the mule. A catar- 

 rhal nasal discharge occurs, highly infectious. In the cutane- 

 ous variety, the enlarged lymphatics or nodes which develop 

 are called farcy-buds. 



Manner of Infection. Glanders, being a highly contagious 



