89 PREPARATION AND MOUNTING 
dry. Amongst the most beautiful and easily prepared of 
these may be mentioned the petal of the geranium, the 
cells of which are well defined and amongst the most 
interesting. 
Sometimes this cuticle is removed by maceration of the 
leaf in water or by a quicker method—boiling in nitric acid. 
Perhaps it will be as well to give Mr. Arnold’s experience. 
“A leaf of a rhododendron which had been dry some 
months, and a freshly-vathered leaf of an azalea, were put into - 
a test-tube, and covered with undiluted nitric acid of com- 
merce of, I believe, about 1°32 specific gravity; the tube was 
held over a spirit-lamp until the acid just boiled, and 
the contents were then thrown into a basin of cold water. 
The cuticle of the rhododendron leaf partially separated 
spontaneously; that of the azalea came off without the 
least difficulty. The whole operation did not occupy more 
than five minutes. Undoubtedly many leaves, according to 
their texture, will require different strengths of acid, and 
longer or shorter periods of boiling.” 
Closely connected with the leaves are the ANTHERS and 
POLLEN, of which a great number are beautiful and interesting 
subjects for the microscopist. 
The mallow tribe will furnish some exquisite objects, 
bearing the appearance of masses of costly jewels. These 
are usually dried with pressure, but the natural form may 
be more accurately preserved by allowing them to dry as 
they are taken from the flower, with no interference except 
thoroughly protecting them from all dust. Sometimes the 
anther is divided, so that the cell required to receive them 
may be of as little depth as possible. The common mallow 
is a beautiful object, but I think the lavatera is a better, as 
it shows the pollen-chambers well, when dried unpressed. 
The pollen is often set alone, and is well worth the trouble, 
as it then admits of more close examination. Often it is” 
convenient to have the anther and pollen as seen in nature 
on one slide, and the pollen alone upon another. The 
former should be taken from the flowers before their fall 
