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plant, as builders use stone or brick, in forming strong and im- 
penetrable walls. Hence we find it largely composing shells of 
nuts and the endocarps of fruits. These, being waste products, 
are for sale at very low prices and in abundant quantity, so that 
they are favorite adulterating substances. Olive pits are very 
largely ground up for this purpose, and their stone-cells are here 
hown. ‘You will at once see how readily these could be detected 
in this powdered aconite root. They are very largely used in 
ground black pepper. 
Those of cocoanut shells are very similar, as here shown, but 
they look somewhat different after the shell has been roasted. 
Both the raw and roasted article have been traded in to the ex- 
tent of several car-loads at asingle sale. They have been used 
with especial frequency for the adulteration of chocolate, the pure 
powder of which is here show 
One of the most interesting of these stone-cells is that in birch- 
bark. After the aromatic oil has been distilled from birch to be 
sold under the name of oil of wintergreen, the residue is useless, 
and it is not infrequently added to powdered drugs. It is not 
only of peculiar shape, but many of the cells have a bright red 
spot, here of course showing black. I have recently found it in 
powdered ipecac. This is a peculiarly villainous form of adul- 
teration, because, as most of you know, ipecac is frequently our 
sole reliance in saving the life of a child attacked with croup. 
ne the most interesting cases of adulteration is that of 
ieee (Spigetia) with the root of Ruellia, which possesses none 
f the properties of the former. So common is this adulteration 
pictures of the powder of Spige/ia were incorrect, that I took some 
roots of each from flowering plants, and gave them to my asso- 
ciate, Dr. Mansfield, for study. It turns out that not one of the 
many descriptions and pictures has failed to describe or illustrate 
the false for the genuine. Here is one of these pictures, and 
there is scarcely an element in it that does not pertain to the 
ia. 
‘Closely related to stone-cells are the fibers of plants, the long, 
