334 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
their axes in the plane of the stage, and move independently of one 
another or together, to any obliquity below or above the stage. A steel 
pin for centering the substage accompanies the instrument. 
Sayre’s Pocket Dissecting Microscope. — Figs. 80 and 81 show the 
instrument sold under this name by Messrs. Bausch and Lomb. It 
consists of a palm-piece or handle, of such length that the lens and 
object to be examined can be held comfortably and easily in one hand, 
while the other hand is left free to dissect the object, or to spread out 
its parts. The arm or post is cylindrical, is very light, and is so hinged 
and socketed that it can be placed in any position and turned at any 
Fig. 80. 
Fig. 81. 
angle. The lens is of excellent quality, and is inserted upon a small 
post about the length of the palm-piece, so as to allow it to be placed 
over the object examined, when held between the thumb and forefinger 
of the hand which holds the Microscope. The instrument will also 
lie firmly on the table, as the handle is provided with a thin piece of 
metal which, when turned at right angles to the handle, supports it and 
the lens in an upright position. Thus the instrument can be used for 
low-power dissections. The arm and lens can be folded into the groove 
in the palm-piece, when the instrument resembles a pocket-knife. 
Bauschlfand Lomb’s Attachable Mechanical Stage. — Figs. 82 and 
83 represent a new mechanical stage, which the designers believe will 
prove capable of preserving its delicacy of adjustment even after pro- 
longed wear and tear. 
The rectangular movements are both by rack-and-pinion, as all 
efforts to produce a perfect worm-screw movement have been unsuc- 
cessful. The rack-and-pinion is preferable, as it is perfectly reliable 
as to wearing qualities, is more sensitive than the screw, and gives equal 
speed to both movements. Millimetre graduations, with verniers, are 
