CLEANING PIPETTES 



21 



5. Rinse again in running water to remove all traces 

 of acid. 



6. Complete the cleaning as described under "new 

 pipettes." 



When dealing with graduated capillary pipettes em- 

 ployed for blood or serum work (whether new or in- 

 fected), much time is consumed in the various steps 

 from 5 onward, and the cleansing process can be mate- 

 rially hastened if the following device is adopted. 



Fit up a large-sized Kitasato's filter flask to a Spren- 

 gel's suction pump or a Geryk air pump (see page 

 43). To the side tubulure of the filter flask attach 

 a 20 cm. length of rubber pressure tubing having 

 a calibre sufficiently large to admit the ends of the 

 pipettes. 



Next fill a small beaker with distilled water. Attach 

 the first pipette to the free end of the rubber tubing, 



FIG. 22. Cleaning blood pipettes. 



place the pipette point downward in the beaker of 

 water and start the pump (Fig. 22). 



When all the water has been aspirated through the 

 pipette into the filter flask, fill the beaker with recti- 

 fied spirit and when this is exhausted refill with ether. 

 Detach the pipette and dry in the hot-air oven. 



Slides and cover =slips (Fig. 23), when first purchased, 



