252 APPENDIX. 
cells of rounded form show themselves under the tubes. The addition 
of anhydrous alcohol causes a very slight movement of oscillation ; the 
yellowish-red-brown color brightens up and becomes yellow; but the 
longitudinal tubes are perfectly apparent, and upon these are seen at 
intervals rounded cells. These celis are unequal, and of three dimen- 
sions ; large, medium sized, and small. In the liquid are seen floating 
perfectly white crystals. 
The addition of the tincture of iodine produces, in time, in certain 
portions of the tubes, a slightly violet hue; but the little cells have 
become colored a deep violet. As to the crystals, of which we have 
previously spoken, they preserve all their whiteness. 
Let us continue our researches. The epidermis and dermis have 
been removed. We next find between the knots long threads of a 
yellowish color, running from one knot to the other, and which may 
be easily removed by hand: they are united together by a kind of pith. 
A specimen of these threads was submitted to the microscope, (magni- 
fied to one hundred diameters,) and despite all my efforts, it was im- 
possible to completely deprive it of its covering of pith. Under the 
glass the appearance it presented was that of a magnificent column of 
stalactite of the most beautiful whiteness. Sulphuric acid colors this 
part of the plant yellow on the edges, and reddish brown throughont 
the rest of its surface ; a continuance of about a quarter of an hour in 
the liquid produces the disaggregation of little grains almost white, but 
bordered with a more roseate hue. 
The addition of anhydrous alcohol produces the complete decolora- 
tion of the portion formed by the separation of the small grains above 
mentioned ; they may be distinguished perfectly isolated from each 
other, and preserving by their arrangement the form of the bark of a 
tree, or, rather, of a lace of dazzling whiteness. As to the portion 
which has not been detached, it preserves its original form and color. 
The addition of a strong proportion of tincture of iodine has not 
changed the color of the grains of which we have spoken; only the 
liquid in which they are held, becomes strongly tinted yellow ; the 
surface seems to have assumed a slightly bluish tint. As to the cells, 
and the portion of the specimen which was not separated, they have 
taken on a bluish violet. Besides this, there is seen the yellow color 
in portions of the cell not changed to blue. 
