1880. ] Microscopic Crystals contained in Plants. 781 
The names that are in italics indicate the families in which I 
have seen and studied the crystals, but only in a few cases their 
- chemical composition. 
Some of these, as the Onagracez and Orchidacez, contain 
large and beautiful crystals. In the vanilla bean, which is a fruit — 
belonging to a species of the latter family, T. F. Meyer, of the 
university class of ’78, has reported and made drawings of the 
crystals. He states that they are composed of the active princi- 
ple of the bean and belong to the second class or crystal prisms. 
It is often supposed that minute substances have no particular 
use, and so it may be thought of these minute crystalline bodies ; 
but generally anything that occurs in such abundance and so 
regularly has some use in the economy of either the animal or 
vegetable kingdom. On the use of the crystals Prof. Gulliver 
Says: “Although the precise use of crystals in the vegetable 
economy may be obscure, it is plain that whatever is constant in 
the plant-must be important, and by no means necessarily of lit- 
tle importance because of such obscurity.” Taking, for example, 
the Cactus family, which abounds in large crystals, some speci- 
mens of which have been reported to contain so many of these 
minute inorganic bodies that it was almost impossible to move 
the plant without breaking it, and when moved it was necessary 
to pack it in cotton with great care, as if it were the finest jewelry. 
A case like this is seldom met with, but as the occurrence of 
crystals is so constant a feature of this family, they must be of 
Some use, which is, as yet, beyond the reach of man’s power to 
perceive, and it would seem ridiculous to say that they have 
no use as some prominent scientific gentlemen claim. 
But such crystals may be of use to man, perhaps in two ways; 
first, when contained in some medicine. : 
It is well known that the disease called “ rickets” is treated, or 
at least has been, with sarsaparilla; now the plant itself contains a 
large number of crystals which are composed of phosphate of 
lime. Query—why may not this plant, in connection with its 
tonic effects, also furnish some of the needed phosphate to 
strengthen the bones ? 
Second, they may be of use to man when contained in decay- 
ing leaves or plants, thus acting as a fertilizer. . 
Again, crystals are sometimes used by the merchant asa test 
for the genuineness of a drug. The quality of rhubarb is often” 
