946 General Notes. 
When the wheel is revolved, the crank is turned, and the upright 
slide rises and falls in a vertical plane, and of course the object- 
carrier, with its micrometer screw, rises and falls with it. As the 
carrier rises a lever connected with a pawl strikes against a screw 
on a separate pillar ; the pawl catches in the toothed wheel-head of 
the micrometer screw and so turns it, and moves the paraffine towards 
the knife. As the carrier descends a section is cut off, when it is 
near the top of its upward excursion, the micrometer screw is turned 
by the pawl, and the next descent produces another section. By 
simply turning the screw against which the pawl lever strikes, the 
number of teeth caught by the pawl, and therefore the thickness of 
the sections may be varied from 1-300 to 1.33 of a millimeter. 
This microtome has been devised to avoid the obvious inconve- 
niences attaching to the rocking and other automatic microtomes. 
Since the first lot of these microtomes were placed in the market, 
some important improvements have been made, among which may 
be mentioned the strengthening of the upright slide in which the 
carrier moves. This improvement secures regularity and precision 
in the movement of the object, and renders the microtome one 0 
the best for paraffine-cutting now in the market. This microtome, 
with one knife in case, is supplied by the Educational Supply Com- 
pany, 6 Hamilton Place, Boston. 
Tuer Eyss or Scorpions.!—In the median eyes, by careful dis- 
section, the soft part may be separated from the lens and cuticula, 
and cut without the interference of these hard structures. The 
tG. H. Parker, “The Eyes in Scorpions.” Bull. Mus. Comp. Zool., 
vol. xiii., No. 6, pp. 174-177. Dec., 1587. 
