20 
ON HYDRANGEA ARBORESCENS. 
addition of hydrosulphate of ammonia changed the latter to dark 
green, the precipitate was separated by nitration, washed, and 
dissolved in water acidulated with sulphuric acid ; with portions 
of this solution, ammonia and solution of potassa caused white 
precipitates ; ferrocyanide of potassium a blueish white precipi- 
tate which soon changed to deeper blue ; ferrocyanide of potas- 
sium produced a precipitate of a dark-blueish-green color, which 
was completely destroyed on the addition of potassa. Tincture 
of galls produced no change. These experiment indicate the 
presence of a proto-salt of iron, notwithstanding the heating and 
exposure to which in incinerating the root it was subjected. To 
confirm this opinion, several other experiments corresponding 
with the above results, were made with the liquid I. 
(p.) The liquid I. was boiled with carbonate and muriate of 
ammonia, to remove lime, and filtered; the addition of phosphate 
of soda caused a precipitate soluble in acetic acid, indicative of 
magnesia. 
(g.) Chloride of barium produced a precipitate but partially 
soluble in nitric and hydrochloric acids, and muriate of ammonia 
showing the presence of sulphuric acid. 
Other experiments indicated the presence of sulphuric and 
phosphoric acids. 
The constituents of the root of Hydrangea arborescens, as the 
above experiments indicate, are gum, albumen, starch, resin, 
soda, lime, potassa, magnesia, sulphuric and phosphoric acids, 
and a proto-salt of iron. In regard to the active principle of the 
plant, the writer must regret that he has not isolated it, if in- 
deed, the activity be due to any individual constituent, or to a 
combination existing in the root ; the latter seems the most pro- 
bable, and, it may be that much of its efiicacy is due to the large 
amount of mucilaginous matter which forms an important con- 
stituent of this plant. But whatever its virtues may be owing to, 
it is to be hoped that the real therapeutic merits of the root will 
be satisfactorily determined by a more extensive, successful 
application of it in cases of the troublesome disease for which it 
has been so highly recommended. 
