Notes . 
273 
Bibliography. 
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brassicae Woron. im Laufe ihres intracellularen Lebens. Flora, vol. lxxxvi, 1899, p. 404. 
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AN ARRANGEMENT FOR USING THE BLADES OF SAFETY RAZORS 
IN THE MICROTOME. — The safety razors now in general use have cheap blades 
of thin steel with a keen edge suitable for cutting sections. The price of a blade is 
so low that it can be discarded as soon as the edge becomes dull, and the labour of 
sharpening is thus dispensed with. The writer has used blades of this type for some 
years for cutting sections by hand, and has recently designed an arrangement for 
holding the blades in a rigid support, so that they can be used in the microtome. 
A blade found very convenient for the purpose is that of the Gillette razor. It 
has two edges. The blade appears to be cut out of a sheet of steel with parallel 
surfaces, so that, apart from the actual cutting edge, the two surfaces of the blade are 
parallel ; it is thus more easily held in a support than a blade with inclined surfaces. 
The arrangement for holding the blade consists of two blocks of steel (a) shown in 
surface view in Fig. 1 and in section in Fig. 2. Each block is wedge-shaped in 
section, and has two plane surfaces inclined to meet at an acute angle. The blocks 
are fastened together at each end by the screws (b) and thus form what is practically 
a razor blade made in two pieces, but without the actual cutting edge. The latter is 
supplied by inserting one of the above blades (c, Figs. 2 and 3) between the two 
blocks. The edge of the blade should project a little beyond the blunt edges of the 
two supporting blocks, and be parallel with them. The adjustment is made easier by 
the fact that the other side of the blade projects beyond the corresponding side of the 
supports. The actual amount of cutting edge that should project can easily be found 
by trial. The less the edge projects, the greater its rigidity ; but it must project just 
far enough for the paraffin block to clear the edges of the steel supports. After the 
adjustment has been made the supports are screwed tightly together. To ensure the 
two supports having a uniform grip of the blade two steel washers (d) of the exact 
thickness of the blade are placed on the screws between the two blocks. Such 
washers are easily made from a discarded blade which has convenient holes in it. 
T 
