250 DR. LANKESTER, ON RAPHIDES. 
Urticace®.—In the milky juice of Ficus elastica ; im the 
tissues of Parietaria officinalis (Henfrey). Single crystals in 
the bark of the common elm (Ulmus campestris, J. Quekett). 
Pomacrea%.—Bark of the common apple-tree (Pyrus Malus, 
J. Quekett). 
Ex.macnacem.—Pith of Eleagnus angustifolia (J. Quekett). 
Conrrer£.—E. Quekett mentions crystals in the bark of 
Araucaria imbricata. 
Crncnonace®.—In the barks of the various species of 
Cinchona (E. Quekett). 
PuytoLtaceacE®.—Phytolacea decandra. 
Cycapace®.—Compound crystals in the stems (Schleiden). 
DioscorracrE®.—Raphides plentiful in the stem and leaves, 
and still more in the perianth and stamens of Tamus com- 
munis, Gulliver. 
I have given the above summary as far as the materials 
within my reach will enable me. I know it is very imper- 
fect, but I believe, with Professor Gulliver, that the subject 
is deserving of more attention than it has yet received, and 
offers a capital field of investigation for the microscope. 
Mr. Gulliver has set a good example in detailing the facts 
which he has recorded in the life-history of our common 
plants. The biography of our indigenous plants has yet to 
be written, microscope in hand, and it is not till the minute 
details of the cell-life of each plant has been recorded, that we 
shall be in a position to arrive at the laws which govern the 
life of the vegetable kingdom. 
Before concluding, I would add a remark or two on the 
uses of raphides. Link first propounded the notion that 
the raphides were an abnormal condition, and resembled 
calculi in animals, and Edwin Quekett regarded them as acci- 
dental deposits. He succeeded, in fact, in forming artificially 
oxalate-of-lime crystals im rice-paper, by immersing it first in 
oxalate of ammonia and then in lime-water. This experiment, 
indeed, showed that the formation of these crystals might be 
the result of chemical laws, but it did not show that the 
chemical force was not counteracted by other forces connected 
with special conditions of the plant. Professor Gulliver’s 
observations with regard to the Lemnas are especially inter- 
esting, as showing that plants closely connected in structure, 
and living under the same external circumstances, neverthe- 
less produced these crystals in very different quantities. 
The persistence of the same crystals in the same plants 
clearly indicates that there is a relation between these bodies 
and the life of the plant. 
Some physiologists regard the raphides as representatives 
