110 PHOTO-MICROGRAPHS. 
very tenaciously to the surface, or in the stomata. 
These may usually be gotten rid of by soaking 
for a considerable time in water or in alcohol. 
When the specimen is thin and quite trans- 
parent, water will be the best medium in which 
to mount it; otherwise glycerine will be prefer- 
able. 
Puant Harrs. 
The appendages to the epidermis of leaves and 
stems, known as plant hairs, are interesting 
objects both from a physiological and a morpho- 
logical point of view. They offer the greatest 
diversity as to form, and some are very beautiful 
objects under the microscope. The stellate hairs 
upon the leaves of Deuzia scabra (Plate IX, 
Fig. 2) are especially well known to amateur 
microscopists. Stellate hairs are also found upon 
the leaves of the tree mallow (Lavatera ascergenti- 
folia), and doubtless upon many other plants. In 
the throat of the corolla of snap-dragon will be 
found a little tuft of very curious and pretty hairs, 
each of which has a spherical head supported by 
a slender stalk, Cotton is an elongated vegetable 
hair. 
Some ingenuity will have to be exercised in 
preparing objects of this kind for photography. 
Hairs that are closely applied to the surface of 
the leaf may be photographed zz situ by mounting 
the epidermis, or by reflected light. Others will 
require to be detached, and may be shaved off, 
with a razor and mounted in a very shallow cell 
in water or in glycerine. 
