THE BACTERIOLOGICAL LABORATORY 43 



then ready for the nutrient fluid and subsequent 

 sterilisation. 



Fig. 17 F and H represent Pasteur's flask and 

 tube, both of which are provided with caps. The 

 narrow portion of each cap contains a plug of 

 cotton-wool. De Freudenreich's flask is somewhat 

 similar to that of Pasteur. These are used for the 

 cultivation of microbes in bouillon. In Pasteur's 

 pipette flask (Fig. 17 L), the tube above the bulb is 

 contracted twice, and on either sides of these con- 

 tractions there are plugs of cotton-wool. The portion 

 below the bulb is bent twice and is drawn out to a 

 capillary point. The flask is charged with bouillon 

 and inoculated by aspiration ; and then the capillary 

 point is sealed in the Bunsen flame. Miquel's 1 

 bulb tubes (Fig. 17 K and i) are similar devices. 



The tubes and flasks T, M, K, P (Fig 17) are pro- 

 vided with lateral arms drawn out to fine points, 

 and with necks plugged with cotton-wool. They 

 are filled by aspiration and are convenient for storing 

 sterilised bouillon. ' The sealed end of an arm is 

 nipped off with sterilised forceps, the sterile bouillon 

 aspirated into each limb, and the arm again sealed 

 in the flame; a series of such tubes and flasks can 

 be arranged upon a rack on the working table.' 



Sternberg's bulbs (Fig. 17 D) are generally kept 

 in stock in the bacteriological laboratory. They 

 are readily prepared by blowing a bulb on a piece 

 of glass-tubing, and then drawing the tube out to 

 a fine point which is hermetically sealed. To fill 

 a bulb, it is first slightly heated, then the sealed 



1 Lea Organismes Vivants de I' Atmosphere, 1883. 



