ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
573 
The microtome for paraffin series is shown in fig. 89. A heavy cast- 
iron frame B, supported on four feet, carries between its projecting ends 
E E a massive axis A, which is rigidly connected with a, horizontal 
broad arm D. The parallelogram piece has its arms h li at s' s' attached 
to the axis A, and at s s to a cross-piece c parallel to the axis A. This 
cross-piece c has on the left a screw for fixing the clamp K for the pre- 
paration. The arm D carries on its free end two vertical cheeks d d, 
between which is the toothed wheel R. The axis of the toothed wheel 
Fig. 89 . 
is a micrometer screw, which engages in a nut of the arm d. The 
conical ends of the micrometer screw, one of which is visible at a, abut 
against two pieces screwed to the arms li h of the parallelogram. Since 
the nut of the micrometer-screw is fixed, a turn of the toothed-wheel will 
result in a displacement to right or left of the parallelogram and of the 
clamp for the preparation attached to it. The whole apparatus, sup- 
ported by the axis A, can be raised and lowered about this axis. This 
movement is effected by means of an excentric, which is attached to the 
