384 
Transactions of the Society. 
The apparatus shown in fig. 3 does all the work of any device 
hitherto described, and has the advantage of being extremely 
simple to make. All that is required is a carefully selected glass 
Luer syringe of about 2 cc. capacity, a piece of fine brass tubing 
of about 2 mm. outside diameter and 18 in. long (small, extra 
soft brass tubing used for lighting purposes is also serviceable), 
a metal rod 1 in. long with a hole through it large enough to 
receive the brass tubing, a piece of ^ in. glass tubing, some de 
Khotinsky cement or ordinary sealing-wax, and an ordinary small 
horseshoe clamp. 
First seal the metal butt of the Luer syringe to one end of the 
brass tubing. Slip the metal rod over the tubing and cement it 
an inch or two away from the syringe attachment. At the other 
end of the brass tubing seal a short piece of J in. glass tubing, the 
free end of which has previously been drawn out into a capillary 
an inch or so long and about one millimetre in inside diameter 
(fig. 3 2 ). 
When cementing the brass tube to the syringe attachment and 
to the glass tube have a wire inserted far into the brass tube before 
applying the cement. The tip of the brass tube, from which the 
wire projects, is then coated with cement, and the part to be 
cemented pulled over it. While the tube is still warm withdraw 
the wire with a gentle twirling motion. This draws the cement 
out around the ends of the brass tube on the inner surface of the 
projecting glass tube, and prevents the formation of pockets in 
which air may be trapped. In the make-up of the entire system 
one must exercise care to prevent air from being trapped, for the 
presence of the air bubbles vitiates the accurate control of pressure 
in the apparatus. 
The brass tube where the metal rod encloses it is to be 
clamped to the foot of the microscope, or to a base which is 
rigidly attached to the microscope (fig. 3). The short end of the 
tube projecting from the rod is bent, so that the syringe, when set 
into its butt, stands more or less upright. The long end of the 
tube is carefully curved and bent, so that the glass tube which is 
sealed on the end will rest in the needle carrier of the micro- 
manipulator and its capillary project over the stage of the micro- 
scope with its end about 1J in. from the field of the microscope 
objective. 
The Luer syringe must now be charged with distilled water 
which has been boiled, and the apparatus filled to within ^ in. from 
the tip of the glass capillary. Before stopping, however, it is well 
to run water through the apparatus for some time to drive out all 
the air. Before charging the syringe for the last time the plunger 
should be vaselined or oiled. This much of the apparatus is to be 
left permanently ready for use. 
The micro-pipettes are made from micro-needles drawn out of 
