bone i 
r. 
sal 
ga 
1883.] Microscopy. 997 
and cc, and round these the clamp can be turned, a being verti- 
cal, and ġġ and cc hori- 
zontal. In all positions 
these three axes can be 
rier supporting the clamp 
and object. The details 
Ai 
4.—Clamp to be turned in three direc- 
Fic. 
tions (as seen from above). 
partly new, and are ver 
solid and durable. Their arrangement is such as to admit of a 
division of the circles in which the clamp can be turned. a 
nother improvement has been devised by Mr. Jung. This is 
an arrangement which regulates the movement of the microme- 
ter-screw in such a way that after a given number of divisions of 
the drum, a spring registers to the ear and finger of the manipu- 
lator the number of micromillimeters which the object has been 
raised. These intervals can be varied, within certain limits, by a 
simple adjustment comparable to a vernier. The construction of 
this apparatus is decidedly very elegant, but the divisions of the 
drum of the micrometer-screw are so large and easily visible, 
even to weak eyes, as in Professor Thoma’s opinion to make such 
complications useful only for very special conditions. 
ther improvements by different manipulators relate merely to 
secondary points, and do not touch the essential principles of 
construction. 
and it can then be adjusted on the 
gummed cork and plunged again into 
alcohol. The latter will, in a few 
hours, harden the specimen as well as 
he gum, and we obtain a preparation 
like F ig. 5. ; 
These methods are sufficient for the 
great majority of cases, and the differ- 
e 
i : Fic. 5.—Hardened specimen 
oom and V getable tissues can 4 adapted to cork a. 
to their structure, between 0.030 and 0.005™™ Sometimes, how- 
ever, and always if sections of extreme delicacy are required, it 
