PROTECTION 29 
Mineral secretions of one sort or another commonly 
act as a defensive weapon in the vegetable world, 
but some practice is required to discover them. 
A very common and rather pretty plant in many 
parts of the country is the Enchanter’s-nightshade, 
and its leaves are protected 
from small marauders in a 
most interesting way. Many 
of the cells contain very 
small bundles of needle-like 
crystals each of which has 
the advantage, so far as the 
plant is concerned, of a sharp 
point at each end. : 
Although the longest of —==——- 
them are hardly more than Fie. 11.— Needle crystals 
about ;4, ofaninchinlength — (Raphides) of the" sane. ? 
there is no difficulty about shade. (a) R = Raphides, 
seeing the bundles for our- 1; Hair gn margin of leat 
selves. We must take a leaf raphides. x 100. (c) Single 
and drop it intoa small, well- — *TY8t#-_—_ 100. 
corked bottle of methylated 
spirit and leave it there for a few days. The spirit 
will extract the green pigment from the cells of the 
leaf, and when we remove it we shall find it has 
lost all trace of that colour and is quite brittle. 
We need only hold it up to the light while still wet 
in order to see, with a lens, the bundles as short 
distinct lines; but if we want to examine the needle- 
like crystals of which each of them is composed it 
will be necessary to use a microscope. 
This is by no means the only sort of crystal that 
is to be found in plants, but the others cannot be seen 
with so little trouble. 

