96 



CLINICAL BACTERIOLOGY. 



gelatin. In this way a gelatin stab-culture (Fig. 26, a) is 

 obtained. 



Agar, and often also gelatin, is generally solidified so as 

 to yield a slanting surface for inoculation, the point of the 

 needle being passed from below upward upon the surface 

 of the culture-medium (streak-culture). (Fig. 26, b.) Inoc- 

 ulations upon potatoes are made in exactly the same way. 

 a b In the preparation of a bouillon- 



culture or a milk-culture the 

 mass of bacteria is rubbed simply 

 on the inner surface of the tube 

 below the level of the bouillon 

 or the milk, the loop used for 

 the inoculation being then thor- 

 oughly shaken. 



In order to inoculate one test- 

 tube from another, to continue 

 the pure culture further, the two 

 tubes are grasped between the 

 ringers (Fig. 20) (the first tube 

 between the thumb and the 

 index-finger, and the second 

 tube between the index-finger 

 and the middle finger), their 

 stoppers are removed (the one 

 being held between the third and 

 fourth, and the other between 

 the fourth and fifth fingers), and 

 from the first tube there is 

 taken, with the platinum needle 

 previously sterilized in the flame, 

 or, in the case of fluid culture- 

 media, with the platinum loop, a 

 small amount of the culture, 

 which is then conveyed upon or 

 into the new culture-medium. 



The reinoculation of pure cultures that it is desired to main- 

 tain must be repeated at intervals of four weeks. 



The development of gelatin-cultures is permitted to take 

 place at room-temperature, or in the thermostat at a tem- 

 perature of 24 C. (75.2 F.) or 26 C. (78.8 R). The 

 remaining cultures are, however, usually kept in the ther- 

 mostat at a temperature of 37 C. (98.6 F.). A thermo- 



Fig. 26. Stab-culture (a) ; streak- 

 culture (). 



