48 
ON THE JAMAICA DOGWOOD. 
of the mosquito, and having dropped into one glass as 
much of the tincture of opium as was necessary to make 
them fall motionless to the bottom, I added an equal num- 
ber of drops of the dogwood tincture to the other, with a 
corresponding effect. I then decanted the supernatant li- 
quor, and washed the mass of animalculae in each glass with 
fresh filtered water from the dripstone'; after a few ablu- 
tions, those which had been stupefied by the tincture of 
opium recovered, and swam about with their wonted viva- 
city, while all my efforts to revive those acted upon by the 
dogwood proved ineffectual." 
Dr. Hamilton subjoins certain cautions as absolutely ne- 
cessary to be kept in view. " First, the bark of the roots 
should be collected about the period of the full moon, in 
April, at which time the tree is in full flower, or coming into 
flower, and the leaves have not yet unfolded. Next, that 
the best rectified spirit alone should be used in making the 
tincture — the active principle of the bark being only soluble 
in spirit, and precipitating on the addition of water, with 
which it makes a milky compound. It is impossible that a 
longer maceration than I employed might be successful in 
extracting more completely the active principle ; but it 
might be desirable to divide the tincture so obtained, keep- 
ing that made during the first twenty-four hours distinct 
from the second, or making a portion with twenty-four 
hours' maceration, and another portion with forty-eight 
hours' or more ; and comparing, by some common test, the 
relative qualities of each. The following is the formula for 
the tincture I used : 
Ji. Pulveris crassi Corticis Radicis Piscidise Erythrinae, ; 
Spiritus Vini Rectificati, flgiv. 
Macera simul per horas viginti et quatuor in vasi aperto et 
cola. Dosis flsj et infra ex haustu aquae purse." — Phar- 
maceutical Journal. 
