ON EXTRACT OF INDIAN HEMP. 
195 
ART. VI.— ON EXTACT OF INDJAN HEMP. By Andrew Ko- 
bertson, Esq., Professor of Chemistry to the Medical College, Cal- 
cutta. Communicated by Messrs. T. and H. Smith, of Edinburgh. 
A number of pounds of the extract of hemp were pre- 
pared by me — I think upwards of thirty in all— for the pur- 
pose of having its medical properties fully tested by Euro- 
pean medical men. A quantity went to Paris, another to 
Berlin, another to London, sent by different parties, and 
for my share of the matter I sent four pounds of it to Scot- 
land, part of which went to you. I do not care about 
making more of it, as its preparation is most tedious and 
troublesome, in which I was tormented by the Excise regu- 
lations of the country, for both the plant and the spirits used 
are the subject of heavy duties and stringent precautions, 
and the cost price of the extract to me, counting nothing for 
trouble, was fully fifteen shillings per lb. Dr. O'Shaugh- 
nessy made his extract with alcohol, in a Papin's digester, 
at a heat above the boiling point of alcohol — the extract so 
obtained is brown; mine is of a deep green, and gives a 
grass green tincture to alcohol, and has six times the activity 
of the brown, as ascertained by trial on hospital patients. If 
a speedy effect is desired it is given as a tincture ; if a de- 
ferred and protracted, as a pill. 
As the process by which it was prepared is an idea of my 
own, since copied by others, and which probably may be 
claimed by them afterwards. I may mention it to you. It 
is a variation of the process of percolation, alcohol in 
vapour being the agent. A still was charged with strong 
spirits, and its nose introduced into the side of a cask in 
which the plant was pushed. 
The vapour of the alcohol, and alcohol at a boiling heat 
