536 BOTANICAL GAZETTE [DECEMBER 
greater, the spring at de prevents the upper ends of the material holder 
from spreading and insures maximum pressure against the material at 
these upper ends. Finally the stem is held firmly in the center of the 
tube or well of the microtome between the leaves of the material holder. 
The pressure screws are free to move up or down in their openings 
because no appreciable pressure is exerted upon the walls of the tube 
or well. 
In a similar manner material held in pith is very conveniently 
arranged in this apparatus. The possibility of arranging and orienting 
such material held in pith in the material holder outside the microtome 
is an obvious advantage. Longitudinal sections of small woody stems 
are readily cut in this modified hand microtome, whereas their small 
diameter makes it very difficult to secure them firmly in the original 
apparatus. As may be seen, it is possible to orient material to obtain 
all angles in the case of sections to be cut obliquely or in the case of 
unsymmetrical material. 
This modified hand microtome was devised to meet a special need 
and has admirably served its original purpose. This description of 
it is presented primarily because it illustrates the possibility of modifying 
an apparatus in a relatively simple and inexpensive manner to increase 
greatly its convenience and the range of its usefulness. The original 
modification from which the drawing was made has been somewhat 
improved recently. The knurled heads 6b should be much larger than 
those illustrated, and for woody stems the leaves of the material holder 
should be thicker and their inner surfaces more nearly flat.—T. H. 
GoopsPEED, University of California. 
