112 PHOTO-MICROGRAPHS. 
which, moreover, is as yet only imperfectly 
worked out. The student, therefore, keeping in 
mind the general rules which have been given, 
will have ample scope for the exercise of his own 
ingenuity. 
SECTIONS OF VEGETABLE TISSUES. 
Photo-micrographs are especially well adapted 
as illustrations of vegetable histology; and the 
ease with which sections of vegetable tissues 
are made and mounted for the purpose, as well 
as the beauty of the result, cannot fail to make 
this one of the most popular applications of the 
art. 
Sections — transverse, oblique, or longitudinal 
are quickly made with a sharp razor from the 
petioles of leaves; from succulent stems, like the 
new growth of asparagus, geranium, etc.; from 
bulbous roots and tubers; from endogenous 
plants, such as canna, maize, ete. ; and from recent 
sprouts on exogenous trees and shrubs. 
No section-cutter is required for this purpose ; 
and every one engaged in work of this kind 
should make himself an expert in free-hand 
section cutting, as many of the best photographs 
are made from extemporaneous preparations. 
The proportion of mounted preparations in 
animal and vegetable histology, to be found in 
every collection which are xot suited for photo- 
graphing, will surprise one who attempts to save 
himself the trouble of mounting his own speci- 
mens for the purpose. 
