678 PHARMACEUTICAL BOTANY 
screw seen on the side of the tube, or it may first be inclosed in 
elder pith or cork and then clamped in. The object to be sec- 
tioned is raised a little at a time through the hole in the glass 
plate at the top by turning the finely graduated feed near the 
base of the tube. ‘The section razor is then laid flat on the glass 
plate and pulled across the object with a long sliding motion. 
The upper surface of the razor blade is 
kept wet with 50 per cent. alcohol and 
after several sections have been cut they 
can be swept by the finger or camel’s 
hair pencil to a dish of water. Each 
division of the feed represents 10 microns, 
so that the thickness of sections desired 
can be regulated by moving the feed, 
accordingly, just before each stroke of 
the razor. 
Suipinc Microrome.—This type of 
microtome (see Fig. 506) is adapted for 
cutting all kinds of sections. It consists 
of an iron supporting frame of horizontal 
and upright portions. The horizontal 
base rests on the table and is hollowed 
out to accommodate a drip pan that 
Fic. 505.—Hand microtome. can readily be removed and cleaned. 
Descuipeiodt tp text. The front of the upright portion 
exhibits a frame which accommodates a sliding feed mechanism 
to which is attached the object carrier, ‘The top of the upright 
portion shows a flat bed which carries a solid iron block 
which can be readily slid along the bed when the latter is lubri- 
cated with paraffin oil. The upper surface of the block js 
grooved to accommodate the thumb screw. The microtome 
knife consists of a blade portion that is flat on its lower and 
hollow ground on its upper face. The latter is placed in the 
clamp on the top of the microtome, and its position adjusted. 
Sections of woody material can be cut directly on this microtome 
and placed in dilute alcohol. When paraffine sections are cut 
the cutting edge of the knife should be parallel to the motion; but 
when celloidin sections are desired the knife must be set at an 
