THE OLIVE TUBERCLE : CAUSE 



397 



non-milk-curdling, chloroform-tolerant, sodium chlorid-sensi- 

 tive, acid-sensitive (but not to the acid of Cohn's solution), 

 alkali-sensitive, slightly viscid (7th daj^ on agar, 3rd day on 

 steamed potato), rod-shaped, or occasionally short filamentous 

 or catenulate (up to 10^ or 15^, rarely 40^) schizomycete, forming 

 on the surface of +15 peptone-beef agar poured-plates slow- 



FiG. 305. — A detail from Fig. 304 in the channel of infection, showing the bacteria. 

 Tissues slightly out of focus. XlOOO. 



growing colonies, translucent at first then pure white, which 

 on thin-sown plates at 22°-23°C. may be 1.5 to 3 mm. in diam- 

 eter at the end of the third day (2 to 5 mm. at the end of the 

 7th day) and are circular, flat, smooth, glistening, and entire, 

 or nearly so (Fig. 310), the internal structure under the micro- 

 scope being amorphous or fine granular; the buried colonies 

 are quite small and often biconvex. Young and perfectly 

 smooth surface colonies may also show for a short time a 



