1880. ]. Microscopic Crystals contained in Plants. 721 
Thus not a single species belonging to the order Onagracez or 
Galiacee was without a note of raphides, while in no single 
instance were these acicular crystals noted in the next allied 
orders.” A converse example is then given. He then proves by 
more extended experiments that raphis-bearing is essential 
throughout the lives df certain species. By this and other experi- 
ments that I might mention, it is shown that the form and posi- 
tion of microscopical crystals in plants may be used as a distinc- 
tive character between orders especially, and perhaps to a certain 
extent, between genera and species(?). Plant crystals as a char- 
acter would only be of benefit to the botanist who had at hand a 
microscope that magnified at least a hundred and twenty-five 
diameters, Hence the objection to making them a means of 
identifying plants in our works on systematic botany. 
As to the history of crystals, Lindley states that they were 
first seen by Rafn, who found them in the milky juice of some 
species of the family Euphorbiacez, and that they were afterwards 
seen by Jurine in the leaves of Leucoium vernum and elsewhere. 
Edwin Lankester, M.D., writing on raphides, credits Malpighi 
with the discovery of crystals in plants, who found them ina 
species of Opuntia, and he says, further, that they were after- 
wards described by Rafn as occurring in the milky juice (latex) 
of some plants belonging to the family Euphorbiaca, and that 
Jurine soon after found them in the leaves of Lewcoium vernum as 
Stated by Lindley. 
Raspail seems to have been the first person who studied crys- 
tals with their chemistry in view, at least he was probably the 
first to demonstrate that some of the crystals were composed of 
calcic oxalate. 
John Quekett, inva paper written in or about the year 1852, also 
gives the credit of the discovery to Malpighi, and says that they 
were subsequently described by Jurine and Raspail, as stated above. 
Prof. Gulliver says that the raphides so early mentioned by Rafn 
in the Euphorbiacez were only the starch-rods which he (Gulli- 
ver) described as having found in the latex of the British Spurges. 
Crystals should be divided into (at least) three classes and 
these seem to cover all the ground that was formerly covered oes 
me name “ Raphides.” They are as follows: : 
I. Raphides. 
2. Sphzraphides. 
3. Crystal prisms. 
