AND HISTOLOGY OF PIPER BETLE. 279 
grouped together in small or 
and angular in outline. They often appear 
large numbers, and form balls of an irregular shape. The hilum cannot be 
made out. The lamellie also cannot be discerned. No compound grains, 
unless these be the balls just referred to, occur. Regarding distribution of 
starch within the plant-body, a heavy deposit is to be seen in the root and 
stem at particular seasons. The precise cells containing starch have been 
mentioned in the preceding anatomical account of the root and stem. 
These are met with in the general 
Crystals of Сеит Oxalate. 
parenchyma of the entire plant. The epidermis and aqueous tissues do not 
contain any. The assimilatory cells of the leaf are particularly laden with 
this salt. No definite crystal sacs are formed. The crystals either take an 
oblong shape or appear as very minute particles, with Brownian movement. 
No crystals of other salts were observed. 
Mucilage.—-This occurs in regular canals of lysigenous origin. The canals 
are quite absent from the roots. In the normal lamina there is only one of 
these fully developed occupying the midrib, In the tissue of the leaves 
reduced to mere sheaths there are a dozen of them running lengthwise from 
base to apex. In the stem they occur in the parenchyma of the stele, as 
already described. The mucilage is completely soluble in water. 
Potassium Nitrate-—This substance was found by my friend Mr. D. 
L. Sahasrabudhe, of the Chemical Department, Agricultural College, Poona, 
to occur in extraordinary abundance in various parts of the plant. It can be 
readily detected in the leaves and axis microchemically with diphenylamine 
and pure sulphurie acid. 
Tannin.—As made out by the usual microchemical reagents for tannin, 
this oceurs in very small quantities, since only very faint reactions can be 
obtained. No special tanniniferous cells occur. 
“ssential Oil.—Secretory cells containing an essential oil occur throughout 
the plant. In the leaf they are particularly abundant. They always occur 
singly. These cells are usually larger than the surrounding parenchyma. 
They attain their full size at a time when the neighbouring tissues are in an 
embryonic stage. The oil takes up a greater part of the space within the 
cell and forms, asa rule, a single large globule. Besides the oil the cell may 
contain starch-granules and crystalline particles of calcium oxalate. The 
best way to examine these secretory cells is to strip off the lower epidermis 
of the blade with the fingers. The aqueous tissue which is interspersed with 
these cells also comes off with the epidermis. With pure sulphuric acid 
the secretory cells give the following reactions. The oily contents at 
once turn yellow. Almost immediately the yellow changes into orange. 
The orange after two or three minutes changes into light crimson, and this 
after a few minutes (from 5 to 30) passes off into faint purple. By the time 
the crimson colour is developed the cells burst, liberating the contents. 
