250 MR. C. DARWIN ON THE ACTION OF CARBONATE 
cells included a few small spheres of dark brown matter instead 
of granules. Usually the cells containing the granules formed 
single longitudinal rows, which alternated with rows of colourless 
cells. But occasionally several adjoining rows included granules: 
thus in one place two adjacent rows of cells with granules were 
succeeded by an empty row ; this by two alternations of granules 
and empty rows; then came two adjoining rows with granules, 
an empty row, and three adjoining granular rows. In another 
place an empty row was succeeded by five adjoining rows with 
granules; these by an empty row; this by three adjoining rows 
with granules, and this by an empty row. 
After many casual observations, in which all the root-hairs 
appeared to arise from cells destitute of granules, this was found 
to be the case with 50 hairs which were traced down to their 
bases. With one problematieal exception, not a single hair could 
be found which arose from a cell containing granules. In this 
one exceptional case, a hair seemed to spring from the transverse 
wall separating two cells; but with a good light and under a high 
power, the wall apparently consisted of two walls, separated by 
an excessively narrow clear space, as if a cell had here failed to 
be fully developed. 
The solution likewise caused the precipitation of granules in 
the elongated cells surrounding the vascular bundle, and in some 
tubes or ducts within the bundle. The solution apparently does 
not act on cells which have been killed. The ends of a root were 
torn open, so that the vascular bundle was fully exposed; the 
root was then left for 24 hours in a strong solution of 7 to 1000, 
and no granules were deposited in the exposed cells round the 
vascular bundle; but by tearing open fresh parts of the same 
roots, these cells were found full of granules. 
The granules were not dissolved by immersion for 24 hours in 
aleohol; but they were dissolved by a cold solution of caustie 
potash. The dissolution, however, took place very slowly; for 
though on two occasions the granules wholly, or almost wholly, 
disappeared after an immersion of 20 hours, yet with a thicker 
root they were not dissolved, though rendered browner, by an 
immersion for this length of time; but they finally disappeared 
after 18 additional hours in a fresh solution of the potash. In 
the cells round the vascular bundle, from which the granules had 
been dissolved by the potash, matter resembling oil-globules in 
appearance remained. 
