PIPETTES 51 



of platinum wire in a handle of glass rod. One end of 

 a glass rod is softened in the Bunsen or blowpipe flame, 

 and about an eighth of an inch of the platinum wire is 

 embedded in it with a forceps, the wire having been first 

 heated to a red heat. The glass- wire joint is then well 

 annealed in the flame and allowed to cool slowly. Metal 

 handles may also be used. Two thicknesses of platinum 

 wire are desirable, viz. 04 mm. (27-28 B.W.G.) for most 

 purposes, but a thicker wire of about 0-7 mm. where 



FIG. 6. Platinum needles. 



stiffness is required, and one or two 3 in. or more in length 

 are useful. 



Forceps, needles, etc. Several forceps are necessary, the 

 ordinary dissecting form in two or three sizes, one or two 

 pairs of fine pointed, two or three small brass ones, and 

 two or three pairs of the " Cornet " pattern. A few 

 ordinary sewing needles of various sizes mounted in 

 wooden handles serve all purposes. 



Glass pipettes and capillary tubes. These are useful for 

 preserving or storing blood or pus, etc., for examination, 

 for sterile water in making film specimens, and for many 

 other purposes. A blowpipe worked by a foot bellows 

 is required for making pipettes, etc. 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 ; this forms a capillary tube of greater or 

 lesser length and smaller or larger diameter, and it can be 

 sealed off in convenient lengths. To make a pipette 

 proceed in the same way : seal off the capillary tube two 

 or three inches from the wide tube, then heat this close 



