1877.] | The Sledge Microtome. 205 
microscopists acquire skill in cutting only by tedious practice, in- 
volving a vexatious loss of time. The instrument it is proposed 
to describe was invented by a French botanist to avoid this 
difficulty by making the guidance of the knife entirely depend- 
ent upon a mechanical construction. The instrument is so sim- 
ple that two or three days suffice for learning to make sections 
of any desired thickness with it, while it may be used with such 
rapidity that hundreds of sections, all equally good, may be made 
in a single morning. 
The instrument is made of brass, and consists of a flat, oblong 
; base and a vertical partition (Figures 25 and 
26, B) rising from it and running length- 
wise. On each side of this partition there is 
a platform, that on the right-hand side (C) 
runs horizontally along the partition, and 
(Fie. 25.) there is a sledge made to slide on it. The 
End view, }, without the sledges. ylatform on the left-hand side (D) begins at 
one end of the partition, quite low 
down (Figure 25), and rises slightly 
but continuously as it runs along to \ 
the other end of the partition, Fig- N 
ure 26 (B'). This platform carries 
a sledge furnished with a clamp to ol iz 
hold the object to be cut. Both the Cc 
platforms are oblique, as may be seen 
in Figure 25, so as to form together 
with the partition a sort of groove 
which is sufficient to guide the mo- 
tion of the sledges perfectly. The 
principle of the instrument is, that 
the object is shoved up an inclined 
B 
A 
plane on the left-hand side, and is Bs: 
thereby raised. Then the knife, fast- : 
ened to the sledge on the right-hand 
platform, is drawn back, and cuts \ 
through the object, which is then es 
shoved a little further up the inclined 
plane, and the knife when drawn 
actoss cuts again in a plane parallel 
to that of the first cut, and thus a (Fie. 28.) 
slice with two parallel surfaces is re- T cores 
Moved. Of course the thickness of the section is determined by 
