100 
ON A NEW DISPLACEMENT APPARATUS. 
The first substance operated upon was uva ursi in coarse 
powder, and the menstruum, water. The first few ounces 
of fluid which passed was almost colorless, owing to the 
steam nearly all condensing on the cool sides of the dis- 
place^ and passing down its surface without acting to any 
extent on the leaves ; but soon after, the product was highly 
charged with color and taste, and was found to contain 
twenty five per cent of solid extract by evaporation. The 
proportion gradually decreased, until the last runnings pos- 
sessed but little color or taste. When the operation was 
concluded, the leaves were found comparatively free from 
moisture, and the portion nearest the sides of the displacer 
entirely exhausted of astringency. The central part, however, 
retained to a considerable degree its peculiar taste, which 
will be noticed in the sequel. 
The second experiment was with Jamaica ginger, and 
the menstruum used was alcohol. The first part of the pro- 
duct was highly concentrated and colored. The operation 
was continued till as much product had passed, as the 
amount of ginger required for the officinal tincture. The 
last runnings were yet charged with the taste and odor of 
ginger, but very much less so than the first. The tincture 
obtained, however, was fully equal to that made in the or- 
dinary way, and four pints were made in as many hours 
by the heat of a gas burner ; — the time occupied of course 
depends on the greater or less rapidity of the vaporization 
of the menstruum in the boiler, and of its condensation in 
the displacer. 
The third trial was with senna, the menstruum being 
water. It is well known that in treating senna by dis- 
placement, it has been found necessary to use diluted 
alcohol, owing to the large amount of mucilage in the 
leaves. When, however, the water is applied in this appa- 
ratus, no difficulty is experienced, and the operation pro- 
ceeded as successfully as in the other cases mentioned, the 
senna being merely bruised. 
