Notes . 
275 
Several advantages may be claimed for this device. The blades may be bought 
anywhere, and the best two-edged blade costs only 4 d. They can be stropped by 
one of the automatic stroppers already on the market, or else thrown away as soon as 
they become dull. For this reason the arrangement should be of great service where 
large classes of students have to be taught the use of the microtome and would have 
to provide their own blades. A further advantage is that hard or gritty objects can 
be cut at the sacrifice of only a cheap blade, without fear of doing damage to an 
expensive microtome blade of the usual pattern. 
B. H. BENTLEY. 
Sheffield. 
