OF AMMONIA ON THE ROOTS OF PLANTS. 247 
longitudinally striped with very faint brown lines; and one cell 
was observed which included granules; so that plain water pro- 
duces some effect. These same roots, after being irrigated with 
a solution of 7 to 1000, were left for 24 hours; and now the 
longitudinal rows of brown cells had become much darker, and 
presented a much stronger contrast with the colourless cells. 
Several of the brown cells moreover included granules, which 
here and there were aggregated into small dark-brown rounded 
masses. 
Drosera, Dionea, and Drosophyllum.—The roots of the plants 
belonging to these three closely allied genera are strongly acted 
on by a solution of carbonate of ammonia. In the case of a. 
young plant of the Dionca, all the exterior cells of the roots, 
after immersion for 24 hours in a solution of 4 to 1000, contained 
almost black or orange, or nearly colourless spheres and rounded 
masses of translucent matter, which were not present in the fresh 
roots. In this case, therefore, the exterior cells did not differ in 
alternate rows. Near the extremity of one of these roots many 
separate cells in the parenchyma, as seen in transverse sections, 
contained similar translucent spheres, but generally of an orange 
colour or eolourless. The cells surrounding the vascular bundle 
abounded with much smaller dark-coloured spheres. 
Three main or leading roots of Drosophyllum lusitanicum were 
cut off and examined before being immersed in the solution, and 
no aggregated masses could be seen in them. Two were left for 
22 hours in a solution of 4 to 1000, and they presented an extra- 
ordinarily ehanged appearance; for the exterior cells in many 
rows from the tips to the cut-off ends of the roots included either 
one large, or, more commonly, several spherical or oval, or eolumnar 
masses of brown translucent matter. The columnar masses had 
sinuous outlines, and appeared to have been formed by the con- 
fluence of several small spheres. The loose, or almost loose, 
oval cells composing the root-cap included similar brown spheres ; 
and this fact deserves attention. Two rows of cells containing 
the just-described masses often ran up the root alongside one ano- 
ther; and sometimes there were three or four such adjacent rows. 
These alternated with others which were colourless, and contained 
either no solid matter, or rarely a few minute pale spheres. 
These roots were carefully examined; and all the many root- 
hairs arose from the colourless rows of cells, except in some few 
cases in which the cells on both sides abounded to an unusual 
