80 
PROCEEDINGS OF THE 
specimen exhibited, being a portion of the original fence con- 
structed by Mr. Breese, on the estate of Sir Thomas Neave’s, 
at Dagnam Park, Essex. The Secretary read the following 
translation from the Annales des Sciences Naturelles, vol. 8, 
“ On the Formation of Crystals in the Cellules of Plants,” 
by Dr. F. Unger, (translated by Mr. J. Rich). 
Some authors have wrongly maintained that the crystals 
which exist in plants are not found in the cellules them- 
selves, but only in the intercellular passages ; that Avhich has 
possibly led them into error is that these groups of crystals 
are sometimes so voluminous as to distend the cellule and 
give it the appearance of being six times the size it is in the 
natural state. Generally these crystal cellules do not contain 
other organic substances ; nevertheless I have found them in 
the same cellule, mixed with numerous grains of chlorophylle. 
Meyen first discovered crystals in the epidermal cellules, for up 
to that time it was thought that they belonged exclusively to 
those of the parenchyma. To the two plants, the Maranta 
zibrina and Tradescantia discolor, which he has signalized 
as presenting this peculiarity, I can add a third, the Goody era 
repens. However, it is commonly in the cellules of the paren- 
chyma that these inorganic bodies are observed. They exist 
in all the divisions of the vegetable kingdom from the most 
simple Algae (Nostoc muscorum Confera crystallifera) to the 
most perfect vegetables. It is seldom that a single crystal is 
found in a cellule, but this peculiarity is remarked in the 
Papyrus Antiquorum and the Ficus Bengalensis ; but in gene- 
ral each cellule contains several, even in the vegetables we 
have just named. In plants which have ethereal cavities the 
crystal cellules are often empty, and make a projection in the 
interior of these cavities ; this is particularly the case in aci- 
cular crystals, as M. Meyen has shown in his Phytotomia. 
I have observed it also in the crystals disposed in stars of the 
Myriophyllum spicatum. The existence of crystals appears to 
be connected with that of the cellules containing sediment, 
and other substances, such as rosin, chlorophylle, &c. The 
vascular bundles on the contrary have nothing to do with 
the crystalline formations. Let us first occupy ourselves 
with the form of these crystals whose extreme smallness ren- 
ders it exclusively difficult to determine, for nothing positive 
could have been said on this point if the angles that the sur- 
faces make between them had not been measured. M. Raspail 
invented for this purpose his goniomctrical microscope ; 
but this instrument is very difficult to manage, so that the 
limit of his errors be less than the differences which exist 
