150 Association of American Geologists and Naturalists. 
hardest woods—as lignum vite, oak, mahogany, &c., and may be ob- 
tained isolated, by scraping the bark or wood into water, and picking 
out the woody particles. In the ashes of the leaves of many trees, 
every ramification of the vascular bundles was found marked out by 
rows of crystals. In very young leaves these crystals were only found 
along the midriff and a few of the principal veins. These crystals 
were shown to be referable to three principal forms : 
Ist. Form A, being modifications of a rhombic prism, oblique from 
an acute edge, and with the acute edges frequently replaced. ‘This is 
the most abundant form among dicotyledons. 
2d. Form B, to which were referred crystals with the lateral planes 
at right angles, as in hickory, iris, &c.; and, 
3d. Form C, which is the same as the conglomerate raphides of Que- 
kett. 
It was shown that the forms A, B and C, sometimes occur together 
in the same plants; that these crystalline forms all belong to the same 
system; that the identity of the corresponding plane angles rendered 
it probable that all these forms were derived from the same prumary ; 
and that the fact observed by Mr. Quekett of London, that forms A and 
B produced dissimilar effects on polarized light, might be due to the 
light being transmitted along different axes in the two kinds of crystals. 
Tables, accompanied by drawings, showing the occurrence of these 
crystals in a great number of plants, were presented by Prof. B., who, 
in connection with these, remarked on the small amount of crystals in 
the Pine tribe, where they appear confined to the bark, and their appa- 
rent absence in some large groups of plants, as the Labiatee, Composite, 
Gramine, &c. : 
An account was given of the micro-chemical and other experiments, 
proving the composition of the crystals in all the plants contained in the 
tables to be oxalate of lime. 
In remarking on the number of these crystals contained in plants, it 
was stated by Prof. B. that the number contained ina single square inch 
of the liber of many trees, as the willow, poplar, locust, &c., no thick- 
er than a piece of writing paper, was at least a million, and that con- 
sequently the amount in the whole tree, including its bark, wood and 
leaves, must be enormous, and yet nearly all the trees of the forest were 
thus filled with crystals. 
Remarks were then made by Prof. B. on the important questions con- 
cerning the causes and consequences of this vast production of crystal- 
lized oxalate of lime in the vegetable kingdom, and upon the develop- 
ment of heat and electricity which must attend its formation. He sug- 
gested as questions worthy of examination, whether oxalate of lime is 
a fertilizer, whether the fall of leaves, shedding of bark, &c. might not 
