1911] BRIEFER ARTICLES 209 
great rigidity, and also allows the paraffin block to clear readily. The 
curve is easily secured by cutting the two parts of the holder from two 
large brass tubes, one being about 12.5 cm. in diameter, and the other 
fitting as closely within it as an ocular in a microscope. The thickness 
should be about 3 mm. 
2 4 5 
Fics. 1-5.—Fig. 1, back view; fig. 2, front view (toward the paraffin block); 
fg. 3, end view; fig. 4, sectional view at the middle; fig. 5, sectional view at the screws, 
which are represented by the double circles in fig. 1, and by the single circles in fig. 2. 
It is neither necessary nor desirable to have pins fitting the three 
holes in the knife, since they add nothing to the rigidity and even inter- 
fere with the insertion and adjustment of the blade. The binding 
“crews should be as close as possible to the blade, and not at the ends of 
the holder, as shown in the form described in the Annals of Botany. 
With the Gillette blade in this holder, we have cut smooth sections 
2 and 3 » in thickness, and have also cut large sections 2 cm. in diameter 
and 15 pw in thickness, even such refractory objects as the strobili of 
Tsoetes and Selaginella cutting as smoothly as with a first-class micro- 
tome knife in perfect condition. 
