4IO Bulletin 165. 



as small whitish points. Gelatin stab cultures exhibit a white 

 growth extending along the line of puncture. This is com- 

 posed of minute, closely set whitish colonies, and is more vigor- 

 ous near the surface. The surface grow^th in stab cultures pres- 

 ents no important features. 



Bouillon. — In twenty-four hours after inoculation alkaline 

 bouillon becomes slightly clouded and somewhat viscid. A thin 

 gray growth adheres to the sides of the tube at the surface of the 

 liquid, and if the culture is allowed to stand undisturbed, a thick 

 extremely viscid pellicle forms after about a week. It extends 

 gradually from the outer border of the surface towards the cen- 

 ter. Upon displacing the pellicle, the liquid underneath is found 

 to be much less viscid. When the culture is agitated daily, the 

 pellicle does not form and the liquid becomes uniformly viscid 

 throughout. A quantity of white, tenacious sediment is depos- 

 ited. The reaction is alkaline constantly. Cultures a month old 

 or more are extremely turbid, slightly 3'ellowish in color, and 

 contain considerable whitish viscid sediment. The growth is as 

 vigorous in acid boullion as in the above and the reaction 

 becomes alkaline in two days or less. 



One per ce7it solutio7i of sugars in bouillon contained in fermen- 

 tation tubes. — In glucose, lactose, and saccharose bouillon grow^th 

 occurs only in the bulb and the constricted U shaped portion 

 leading to the closed arm. In each one the growth is discon- 

 tinued abruptly at the base of the closed arm, showing the 

 organism to be an obligate aerobe. The reaction in each is alka- 

 line to litmus. Gas is not formed in any of the cultures. 



Potato. — Twent3'-four hours after inoculation a thin growth 

 appears, wiiich is distinguished with difficulty, being of the 

 same color as the potato. Later, the growth becomes more 

 abundant and viscid, assuming a drab color. 



Blood serum, slanted. — The growth first appears as a j^ellowish, 

 viscid mass occup3'ing the line of inoculation, and eventually 

 spreads over the moist portions of the medium. In the upper 

 portions of the slanted serum, where there is relatively less 

 moisture, the spreading of the growth is more restricted. Tree- 

 like branches grow out and anastomose with one another form- 

 ing a net work w^hich covers the surface of the medium to a 

 greater or less extent. 



