WATER 421 



medium is melted, then transfer them to the water- 

 bath regulated at 42 C. Liquefy the nutrient gelatine 

 and wort gelatine tubes by immersing them in the 

 same water- bath. 



4. Remove the bottle containing the water sample 

 from the ice-box, distribute the bacterial contents 

 evenly throughout the water by shaking, cut the string 

 securing the stopper, and loosen the stopper, but do 

 not take it out. 



FIG. 206. Withdrawing water from water sample bottle. 



5. Remove one of the i c.c. pipettes from the case, 

 holding it by the plain portion of the tube. Pass the 

 graduated portion twice through the Bunsen flame. 

 Tilt the bottle containing the water sample on the 

 bench holding the neck between the middle and ring 

 fingers of the left hand ; .grasp the head of the stopper 

 between the forefinger and thumb, and remove it from 

 the bottle. 



6. Pass the pipette into the mouth of the bottle, hold- 

 ing its point well below the surface of the water (Fig. 206) . 



