1314 General Notes. [ December, 
dently of the right half, a’ 0’, or of the screw, g g, by the aid of 
a handle which fits the holes 2 x x. 
When the half æ 4 is adjusted to the half a’ 6’, in the manner 
represented in the figure, the fifteen equal parts into which the 
zone 6 is divided exactly correspond to the same number of parts 
in the zone 4’, so that the grooves which mark these parts in one 
zone, become continuous with those of the other zone. Thus 
adjusted the spring, which rides on the zones 60’ with a sharp 
edge parallel to the grooves, will give fifteen sharp clicks in the 
course of one rotation of the drum, the click being heard every 
time the sharp edge falls into coincident grooves. In order to 
adjust for fifteen clicks, it is only necessary to rotate aé until 
groove fifteen becomes continuous with groove fifteen of the op- 
posite half (a’ 4’). For one click in one rotation, the grooves II 
must be made to coincide; for two clicks the groves 2 2, and 
for three clicks the grooves 33. The intervals between sugoh 
sive clicks may thus be made to correspond to }, 3, 5 Of a of a 
complete rotation of the drum, and the thickness of sections cor- 
responding to these intervals should be respectively .015, 0075 
G5, OOF. 
THE new Opject-Hotper.—The object-holder which res 
companies the Thoma microtome is an invention of Mayer, Andr! 
= 
a 
fh 
ie 
a 
Wis = te See erage 
TLE ML ME Mitel Hittite 
Fic. 3.—The Object-holder and Carrier. : : 
and Giesbrecht, and has been described by them in shep a i 
fore cited. The object is now movable in all three i aa 
is raised or lowered, and turned about the perpendicu pues “oo 
free-hand; but in the two other planes it is moved by Trin de 
that the plane of section may be altered at pleasure, 
