382 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the blade with the handle. The blade (fig. 71, I a, II a, Ilia) is of 
English steel of mean temper. The cutting part is perfectly straight 
and of as simple a form as possible. The blade is plane and slightly 
oblique on its lower surface, but a little hollow on the upper surface 
(VIII). Its back is thick and rounded on two sides for convenience of 
sharpening. The form of the back also allows of the blade being easily 
fastened by means of the clamp to the different sliding microtomes. 
The shank of the blade (II b, III b) is perforated by a square hole (III c), 
and is terminated by a fork set obliquely to the rest of the blade. The 
slot (II d, III d ) between the two branches of the foot (II e,IIIe) serves 
to receive the pressure-screw of certain sliding microtomes (e. g. 
Schanze’s). 
The handle (I /, II /, IV /), of aluminium, has a slight bend 
(I g, II g, IV g ), so as to diminish the quantity of metal of the handle 
and to preserve the blade better when it is closed. The head of the 
handle is pierced on one side with a square hole, and on the other with 
a round one (IV h ), in which the bolt fits. The steel bolt (V, VI, VII ; 
Im, II m) consists of (1) the head at its lower end (V t, VII i), (2) a 
square part (Y j, Vlly), (3) a cylindrical part (V k, VII k'), (4) a screw 
part (VII Z), and lastly (5) a milled head (I m , II m, V m, VI m, VII m). 
The square part of the bolt j fits into the square hole on one side of 
the handle and into the square hole of the blade (III c), while the cylin- 
drical part fits into the round hole on the other side of the handle. 
Rapid Method for Hardening and Sectioning.* — Dr. J. Coats gives 
a method for hardening, of which the principles are rapid hardening in 
alcohol, cutting with the microtome without removing the alcohol and 
without freezing the tissue, and rapid staining. Put shortly, his method 
is as follows : — (1) Select an illustrative part of the fresh tissue and 
remove a slice with a sharp knife. (2) Place in absolute alcohol and 
heat the vessel in a water-bath to about 40° C. for half an hour to an 
hour. (3) Dry the tissue and place it on the freezing plate of the 
microtome in a large drop of anise oil. (4) Freeze the anise oil, which 
freezes at a high temperature, and cut sections. The upper surface of 
the knife may be moistened with alcohol while cutting. (5) Place in 
alcohol to remove anise oil. (6) Float out in water and place on slide 
for staining. (7) Stain by any approved rapid method, and mount. 
(4) Staining 1 and Injecting. 
Examination of Wandering Cells of the Frog.| — Dr. A. A. Kanthack 
and Mr. W. B. Hardy give an account of the methods employed by them 
in the investigation of the wandering cells of the Frog. They find that 
differences in the texture of cell-substance are brought into marked pro- 
minence by the use of iodine, and they say that this reagent cannot be 
too highly praised in this connection. The nuclear type of the various 
cells has been studied with the aid of a solution of methyl-green 
slightly acidulated with acetic acid, and with a drop of osmic acid added. 
The nuclear characters were also shown by treatment with an alkaline 
alcohol-osmic acid solution of methylen-blue. With this solution 
* Amer. Natural., xxviii. (1894) pp. 827-9. 
f Phil. Trans., clxxxv. B. (1894) pp. 283 and 4. 
