378 Transactions of the Society. 
the shaft evenly in the tube. The collar is then clamped into the 
needle carrier of the instrument. This arrangement facilitates 
sliding the needle in or out of the moist chamber without danger 
to the tip of the needle. 
Fig. 3. — Microscope with two micro-manipulators and the micro- 
injection apparatus in place, a, right-handed manipulator on pillar 
set in collar b, fastened to base on which microscope is clamped ; 
c, flexible shaft attached to screw for up and down movement, with 
its milled head at d. (Note that screws for lateral movements are 
controlled by levers.) 
e, left-handed manipulator clamped to left front of microscope 
stage. In its needle carrier is clamped brass collar f, within which 
shaft of needle slides. (See detail in fig. 3 1 .) The coarse adjust- 
ment for raising and lowering needle carrier is done by screw g. 
Injection apparatus, h, Luer syringe set in its butt i, cemented 
to curved brass tube j. This is clamped to base at k ; its other end 
is cemented into glass tube l (see detail in fig. 3 2 ), clamped in needle 
carrier of the right-handed manipulator a. 
Most of the holes in the base are unnecessary. Foot of micro- 
scope is held by two screw clamps. The adjustable guide m keeps 
microscope in proper alignment. 
The micro-manipulator is intended to be used with the mechani- 
cal stage of the microscope. The mechanical stage moves the moist 
chamber (see fig. 3). As the cell or tissue to be dissected lies in 
