PIPETTES AND MEASURES 57 



bending glass tubing a bats-wing gas burner is to be 

 preferred. To make a pipette or capillary tubing a piece 

 of glass tubing is heated in the blowpipe flame until quite 

 soft ; it is then taken out of the flame and the two ends are 

 pulled steadily apart ; the softer the glass and the more 

 quickly and the further it is drawn apart, the finer will 

 be the capillary. By cutting in half, two Wright's pipettes 

 are formed (see Fig. 36, a, p. 260), or the capillary may 

 be cut into short lengths so as to form tubes like those in 

 which vaccine lymph is stored, or by heating the wide 

 part close to where it was heated before and again drawing 

 out a bulbous pipette is found (Fig. 7). Tubes used for 



FIG. 7. Glass pipette. 



vaccine lymph and Wright's capsules (see Fig. 36, d, 

 p. 260), are also useful. 



Graduated Measures, etc. A few graduated cylinders 

 of 10 c.c., 25 c.c., 100 c.c., 500 c.c., and 1,000 c.c. capacity 

 are necessary. For making standard solutions and the 

 solutions of disinfectants for determinations of the 

 carbolic coefficient, some graduated stoppered flasks are 

 necessary ; the usual sizes are 100 c.c., 500 c.c., and 

 1,000 c.c. Graduated pipettes of various forms are also 

 required, e.g. 1 c.c., 2 c.c., 2-5 c.c., 3 c.c. and 5 c.c., bulbous 

 for carbolic coefficient determinations, 1 c.c. straight 

 pipettes divided into hundredths for water examination, 

 and 5 c.c., 10 c.c., and 50 c.c. with central bulb for 

 ordinary measurements. One or two 25 c.c., and 50 c.c. 

 burettes are required for the standardisation of culture 

 media. 



The ordinary 1 c.c. pipettes graduated in hundredths will 

 not measure with any accuracy quantities smaller than 



