BRIEFER ARTICLES 
MODIFIED SAFETY-RAZOR BLADE HOLDER FOR 
TEMPERATURE CONTROL 
(WITH ONE FIGURE) 
The apparatus devised in this laboratory for cutting frozen plant 
material on the rotary microtome! has been found useful in the cutting 
of paraffin sections also, especially when a modification of the familiar 
safety-razor blade holder is employed. For the control of the tempera- 
ture of the knife in cutting paraffin sections LANp? describes and figures 
a trough of metal provided with a nipple at either end in which the micro- 
tome knife is placed and through which water of the desired temperature 
is made to flow. The use of a Gillette safety-razor blade in a proper 
holder is apparently becoming rather general among plant cytologists. 
Certainly the use of such blades with classes in microtechnique is a 
great saving of time and energy as compared with attempts either to 
allow the students to sharpen microtome knives themselves or to pro- 
vide them with such knives properly sharpened. In addition, with such 
a class, consistently successful results in cutting can only be obtained if 
it is possible to regulate the temperature of the knife and, in some cases, 
of the material also. Even at rom with refractory material in 52° 
paraffin it is difficult for most students always to obtain a smooth 
ribbon at ordinary laboratory temperatures unless the knife is kept cool. 
To meet this latter situation a simple modification of the usual type 
of safety-razor blade holder has been employed with such success in this » 
laboratory that a brief description of it seems desirable. We have 
found the original holder made by StricKLER’ the most desirable type 
of a number at present on the market. To such a holder a small brass 
tube is attached, as shown in fig. 1. This tube has a bore of 4 mm. and 
is soldered to the outer leaf of the holder, thus in no way interfering with 
the separation of the leaves when the safety-razor blade is to be inserted. 
The tube is extended approximately 6 mm. beyond the holder proper 
at either end to allow the attaching of small rubber tubes. 
* Garpner, N, L., A freezing device for the rotary microtome. Bort. GAz. 63: 
236-238. 1917. 
2LanD, W. J. G., A method of controlling = -— of the paraffin block 
and microtome knife. Bor. Gaz. 5'7:520-523. 
3 CHAMBERLAIN, C. J., Methods in plant dae Chicago. 1915 (p. 9). 
Botanical Gazette, vol. 66] [x76 
