112 THE AMERICAN MONTHLY [June, 
which presses against the end of the trunnion on the outside of the iron pillar 
on that side of the instrument where the knife is fastened, so that all the sec- 
tions are of exactly the same thickness from first to last. Cutting up large 
objects in the manner above described is not possible with any other form of 
microtome yet constructed. 
Almost any section-knife—wide, or narrow-bladed—will fit into and be 
firmly held by the knife-clamp, which is, however, intended more especially 
to hold an ordinary razor. The best razors for cutting sections have been found 
to be those of the best make only, suchas Wade & Butcher, or Joseph Rodgers 
& Sons, of Sheffield. Only such razors as hold an edge well should be 
used. 
For ribbon-cutting by the paraffine method, the block containing the ob- 
ject, after it is trimmed and soldered to the paraffine with which the holder 
is filled, by means of a heated wire, is covered with a thin coat of soft par- 
affine. This enables one to cut ribbons of any desired length, since the 
softer parafiine at the edges of the successive sections sticks them together by 
their margins as fast as they are cut. 
The ribbons may be allowed to fall upon a slip of paper, which may be 
drawn out, as fast as the sections are cut, from under the bed-plate of the in- 
strument, beneath which there is a space left for this purpose, between the 
three toes or tripod upon which the whole apparatus rests. The edge of the 
knife also remains in the same plane, no matter at what angle the cutting 
edge is placed with reterence to the direction in which the block to be cut is 
moved, just as in the best forms of the sledge microtome. 
The advantages which this new instrument offers are, briefly, compara- 
tively small cost, great efficiency, rapidity, and accuracy. One hundred sec- 
tions per minute may very readily be cut withit. Its simplicity of construc- 
tion, with few wearing parts, and slight liability to get out of order in the 
hands of inexperienced persons, will also commend it to the teacher and in- 
vestigator. Experienee has already shown that those once using it can 
scarcely ever be again induced to use the most efficient sledge or automatic 
microtomes of different design if they can have access to this instrument. 
This device is made by Mr. Zentmayer, whose name is a sufficient guarantee 
of the workmanship employed in its construction. 
Simple life slides is the title of a paper by Dr. A. C. Stokes in the May 
number of Zhe Microscope. In it he describes and figures a number of 
devices which he finds useful in studying living objects. He prefers squares 
of glass to circles for covers, for the greater facility of irrigation with new 
supply of water. He also recommends a shallow shellac cell, made by turn- 
ing a circle and, after drying, removing two opposite quadrants, one above and 
one below. To make another form of cell he cements in the centre a thin 
circle 3, in. in diameter. Then, taking a glass or zinc ring of 4 in. aper- 
ture, he breaks a piece out of one side and cements it around the circle. 
From another ring, % in. aperture, he breaks out a bit and cements it to the 
slide concentrically with the other and the circle and with the breaks of the 
rings opposite each other. A thin, square cover finishes the slide. In using 
this slide a drop of water for study is placed on the inner circle and the cover 
applied. Then a drop of water is placed at the break in the outer ring; it 
runs in and keeps the air in the contrivance moist without reaching to the cir- 
cle, which thus is both isolated and prevented from evaporation. 
oO 
Sections of injected lung may be made, according to a writer in Zhe 
College and Clinical Record, by injecting the lung with gelatin-carmine 
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