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PHARMACEUTICAL MEETING. 
this should be allowed to dry in the air, care being taken to exclude dust. It 
must not be too closely covered, or a viscid film is the result; a dry day should 
be chosen, as in a damp atmosphere it will not crystallize at all. 
The same process answers pretty well for citric and tartaric acids, but the 
solution should not be so strong. It is well to put on six or eight slides of 
these and similar crystals, as only one of them may be good. I have found less 
certainty in obtaining perfect crystals of freely soluble substances than of any 
others; but here, as in all cases, the object to be aimed at is rapidity of deposi¬ 
tion. 
Many substances which are insoluble or nearly so in water, require crystalliz¬ 
ing from spirit of wine, as morphine, strychnine, and many others. The pro¬ 
cess before mentioned, of allowing the substances to crystallize in the solution, 
answers admirably with morphine and strychnine, and, I doubt not, equally 
well with other crystallizable alkaloids. In all cases they should be dissolved by 
the aid of heat, and the solution slightly agitated, to facilitate crystallization. 
Strychnine should be dissolved by heat in a mixture of one part spirit of wine 
and two parts of water. 
Any directions on the subject of microscopic crystals might well be con¬ 
sidered incomplete which did not include the beautiful substance known as 
sulphate of iodo-quinine or “ Herapathite.” These crystals were fully described 
by Dr. Herapath in former numbers of the Pharmaceutical Journal,* who there 
gave the most complete method of preparing them for use as “ artificial tour¬ 
malines,” and also as a test for the presence of quinine. It may not be out of 
place to repeat here what he has written on the subject of preparing the micro¬ 
scopic crystals, which is copied from the Pharmaceutical Journal, vol. xii., page 
217. 
“ A mixture of 3 drms. of pure acetic acid, with 1 fluid drm. of spirit of 
wine, to which 6 drops of diluted sulphuric acid were added. One drop of this 
test fluid placed on a glass slide, and the merest atom of the alkaloid (quinine) 
added ; time given for solution to take place, then upon the tip of a very fine 
glass-rod, an extremely minute drop of the alcoholic solution of iodine added ; 
the first effect is the production of a yellow or cinnamon-coloured compound of 
iodine and quinine, which forms as a small circular spot; the alcohol separates 
in little drops, which, by a sort of repulsive movement, drive the fluid away ; 
after a time the liquid again flows over, and the polarizing crystals of sulphate 
of iodo-quinine are slowly produced in beautiful rosettes. This succeeds best 
without the aid of heat.” 
Made according to this method, the crystals undoubtedly form in beautiful 
rosettes, but the misfortune is that they rarely remain so. Sometimes they 
continue stable, but generally they grow out of proportion and soon become 
shapeless. 
1 have made these crystals by two methods, either of which gives very satis¬ 
factory results. The first method is to slightly modify the fluid spoken of 
above, by mixing 3 drms. of spirit of wine and 1 drm. of acetic acid, thus re¬ 
versing the quantities (as I have generally used bisulphate of quinine, there has 
been no necessity for adding the dilute sulphuric acid). 10 grs. of bisulphate 
of quinine should be dissolved in \ oz. of the fluid, and the solution filtered ; 
10 or 15 drops of this should be poured on a slide, a drop (or more?) of tinc¬ 
ture of iodine added, and the slide tilted a little to allow of the two mixing. 
When the solution becomes clear, it should be poured on to a fresh slide, and 
from that to another, and so on, as long as the liquid holds out, not leaving it 
on a slide, but pouring it on and off again directly ; what remains on the slide 
is amply sufficient for the production of crystals. Some slides will be found 
* Vols. xi., xii., xiii. 
