FUNDAMENTAL CONSIDERATIONS 
15 
MAKING OF SECTIONS 
Free-hand Sectioning. —Free-hand sections are usually satisfactory 
for the general examination of roots, stems, leaves^, barks and many 
fruits and seeds. Material which is fresh may be sectioned at once, 
but dry material should be well soaked in warm water before using. 
Very hard material like heartwoods, the shells of nuts and seeds, 
may be softened in solution of caustic potash or ammonia water 
and then washed free of alkali before sectioning. 
The object to be sectioned is held between the thumb and finger 
of the left hand. If tender and flexible, such as a flat leaf, it must 
be placed between the two flat surfaces of elder pith before sec¬ 
tioning. A segment of pith about an inch long is halved lengthwise 
with a sharp knife and a portion of the leaf is held between the halves 
of pith while the section is cut through pith and leaf. The pith 
is later separated from the leaf section. Sections through other 
delicate parts of plants may be made in the same way, only a groove 
should be made in the pith of such size as is necessary to hold the 
material firmly enough without crushing it. In certain instances, 
when, because of the smallness of the object and its resistance to 
cutting, good sections can not readily be made with the aid of pith, 
a small sized cork stopper can be used with better results. A hole 
just large enough to prevent the object from slipping is made in the 
center of the smaller end and the object inserted preparatory to 
sectioning. The upper surface of the razor is wetted with water or 
50 per cent, alcohol. The razor, which should be real sharp, is held 
in the right hand and is drawn across the o'bject with the edge toward 
the student and the blade sliding on th£ forefinger of the left hand. 
The sections should be cut as thin as possible. As soon as a number 
of sections have been cut, they can be transferred to a vessel of water 
with a camel’s hair brush. 
Sectioning in Paraffine or Celloidin .—When it is necessary to study 
the microscopic structure of very delicate plant parts, superior results 
can generally be obtained by imbedding the material in paraffine 
or celloidin, which is subsequently hardened, and sectioned by means 
of a sliding or rotary microtome. 
