APPARATUS 
9 
the two pieces of the holder are curved, a feature which insures great 
rigidity. It is neither necessary nor desirable to have pins fitting 
the three holes in the blade, since they add nothing to the rigidity 
and even interfere with the insertion and adjustment of the knife. 
The knife should not project more than a millimeter beyond the 
holder. The clamp for holding Gillette blades in the Spencer rotary 
Fig. 4. —Strickler’s clamp for holding Gillette blades in the Bausch and Lomb rotary microtome 
microtome is necessarily much heavier (Fig. 5). With the Gillette 
blade in these holders we have cut smooth sections, 2 and 3 i± in thick¬ 
ness, and have cut large sections 2 cm. in diameter and 15 m in thick¬ 
ness, even such refractory objects as the strobili of Isoetes and 
Selaginella cutting as smoothly as with a first-class microtome knife. 
Fig. 5. —Clamp for holding Gillette blades in the Spencer rotary microtome 
When the success of the holder—or rather, its sale—became evident, 
two prominent optical companies, without any apologies or reference 
to Mr. Strickler, began to manufacture it and advertised it in their 
catalogues. Their holders are inferior to Mr. Strickler’s, doubtless 
because they overlooked a very important, but very obscure, detail. 
Mr. Ralph B. Larsen, 7126 Woodlawn Avenue, Chicago, Illinois, 
makes these holders, selling the holder for the Bausch and Lomb 
rotary microtome at $5.00, and the heavier holder for the Spencer 
rotary microtome at $7.50. 
Many have trouble with the holders, even as made by Mr. Larsen, 
because they fail to remember that the blade is not straight, like a 
microtome knife, but is bent into a curve. Consequently, the 
