12 



GLASS APPARATUS IN COMMON USE 



the point of the blowpipe flame must be used in order 

 to obtain the sharp shoulder at either end of the cen- 

 tral bulb. The terminal tubes must retain a diameter 

 of at least i mm., in order to avoid capillary action 

 during the collection of the fluid. 



For sterilisation and storage each pipette is placed 

 inside a test-tube, resting on a wad of cotton- wool, and 

 the tube plugged in the ordinary manner. As these 

 tubes are used almost exclusively for blood work, 



FIG. 15. Blood pipettes 

 and hair-lip pin in a test- 

 tube. 



FIG. 16. Blood-pipette in metal 

 thermometer case. 



it is usual to place a lance-headed hare-lip pin or a 

 No. 9 flat Hagedorn needle inside the tube so that the 

 entire outfit may be sterilised at one time. 



For the collection of small quantities of blood for 

 agglutination reactions and the like, many prefer a 

 short straight piece of narrow glass tubing drawn out 

 at either extremity to almost capillary dimensions. 

 Such pipettes, about 8 cm. in length over all, are most 



