OF AMMONIA ON THE ROOTS OF PLANTS. 251 
Lastly, two drops of a 1-per-cent. solution of osmic acid were 
added to 2 oz. of distilled water,and some roots were left in this fluid 
for20 hours. They were affected in very different degrees. Some 
were only a little discoloured ; and in such roots a single exterior 
cell here and there contained either blackish granules or small 
black spheres. Other roots were much blackened; and in these 
longitudinal rows of dark brown or blackened cells plainly alter- 
nated with colourless rows. The cells surrounding the vascular 
bundle and many of the parenchyma-cells also contained blackened 
granules. Hence it is probable that carbonate of ammonia like- 
wise acts on some of the parenchyma-cells ; but if so, the fact was 
overlooked, or accidentally not recorded, in my notes. 
Oxalis Acetosella.—Roots were first examined, and then placed 
in a solution of 7 to 1000. Some slight degree of aggregation 
was seen in a few minutes. After 30 minutes all the cells near 
the tips contained rounded accumulations of granules. Higher 
up in one of the roots, single cells, or from two to five cells in a 
row, were filled with minute hyaline globules. In some places 
these had become confluent, so that they formed larger globules 
having a sinuous outline. The cells underlying the exterior layer 
likewise contained extremely fine granular matter. Still higher 
up the same root there were considerable spaces in which none 
of the cells contained granules. But again higher up, the granules 
reappeared. Theroot-hairs were numerous ; but not one was seen 
which arose from a cell containing granules. 
Roots of Oxalis sepium, corniculata, and of a greenhouse species 
with small yellow flowers were immersed in a solution of 7 to 
1000, and granular matter was deposited in the layer of cells 
underlying the exterior layer. This occurred in the case of 
O. sepium in 20 minutes. With O. corniculata the cells with 
granules were isolated—that is, did not form rows; and the 
granules were either brown or of a bluish-green colour. Tn the 
case of Oxalis (Biophytum) sensitiva, the exterior cells of the 
roots, after immersion for 44 hours in the same strong solution, 
were not much affected ; but some of the deeper parenchy ma-cells 
contained dark-brown translucent spheres, and the elongated 
cells round the vascular bundle were almost filled with granular 
matter. 
Fragaria (garden var. of the common strawberry).—Some 
white, almost transparent roots from a runner were examined 
(Dec. 12), and the cells contained no solid matter, except starch- 
