ON DIGITALIS PURPUREA. 213 
the ratio of the dried plant to the proof spirit as indicated in 
the Dublin Pharmacopoeia. I found, from a mean of four 
trials, that 100 grains of digitalis leaves, of a moderate size, 
gathered in dry weather, and immediately dried in a well-re- 
gulated fire-heat, lost seventy-nine grains of water. The same 
experiments made on small leaves proved a loss of eighty- 
three grains for every hundred. 
Thus the mean loss of leaves of a moderate and small size, 
is eighty-one grains, on every hundred ; and the numerical 
strength of the dried leaves is to that of the recent as five one- 
quarter to one. Hence ten ounces and a half, Troy, of the 
recent leaves, would be equivalent to two ounces dried; and 
there would remain eight ounces and a half by weight, that is 
8.94 ounces by measure of water. If to this quantity of water 
contained in the recent plant, we add 8.74 ounces of alcohol, 
(0.814,) we shall have seventeen ounces and a half, by mea- 
sure, of proof spirit, allowing for condensation, (instead of 
sixteen ounces indicated in the Pharmacopoeia for two ounces 
of dried foxglove,) which is one ounce and a half too much. 
But if ninety grains of powder of foxglove be added, the 
whole will be of the pharmacopceial strength, so far as ratio 
of the ingredients is concerned. But the quantity of liquid 
being inadequate to cover the leaves, the bottle containing the 
ingredients should be digested for a month, one day standing 
upon its bottom and the next inverted on its top. The result- 
ing tincture will be of an olive brown color, because the red 
coloring matter observed by Welding will only be dissolved, 
and the chromulite will not. This must happen while we 
adhere to the ratio of the Colleges. But we can obtain a 
brilliant green tincture by regulating the ratio so that the 
menstruum will be reduced to the strength of rectified spirit, 
(0.840.) 
In order to do this, let ten ounces and a half, Troy, of 
leaves be pulled from the growing plant, and plunged into a 
bottle, containing two pints and three-quarters (wine gallon 
measure) of alcohol, 0.815. The strength of the alcohol will 
be reduced by the water to the strength of rectified spirit, 
