ON MICROSCOPICAL RESEARCH IN RELATION TO PHARMACY. 235 
from their containing any active matter which the tincture does not contain, 
but because they are free from certain substances which are retained by it. 
Narceine, meconine, and meconic acid are believed to be inert, whilst nar- 
eotine possesses properties widely different from those for which opium is 
usually employed. Of the bulkier constituents, the resin appears to be worse 
than useless, whereas the bitter extractive, though opinions differ with re¬ 
gard to its precise properties, seems at any rate to increase the narcotic power 
of the more active constituents. A typical preparation of opium should 
therefore at least contain the whole of the morphine and codeine, with me¬ 
conic or some other acid to keep them in solution, and the bitter extractive. 
Codeine itself, and the salts of both codeine and morphine, are readily solu¬ 
ble in either water or alcohol, the remaining principles are fully dissolved by 
alcohol, but scarcely soluble in water; hence, in the preparations alluded to, 
water rather than alcohol is used as the solvent. 
The process we adopt in examining the constituents of a fluid preparation of 
this sort under the microscope is a very simple one. 
Having, as a preliminary step, taken the specific gravity, and ascertained 
the percentage of carefully dried extract contained in it, we evaporate a 
small quantity, usually from four to six drachms, on a sand-bath in a watch- 
glass, to about the consistence of treacle. It is then poured upon a slip of 
glass and covered with a piece of thin glass, and after standing a few days, it 
is sealed in with gold-size. Crystallization sometimes commences before the 
preparation is removed from the watch-glass, sometimes immediately after 
transferring to the glass slip, but in many cases not for several days. The 
time taken is dependent on one of two influences, viz. the quality of the 
opium, and the exact degree of inspissation. 
In determining the value of a preparation from the appearance of this ex¬ 
tractive under the microscope, we do not rely entirely upon the amount of 
crystallization, it is requisite to go one step further to obtain the full value of 
our labour, and by investigating the form and physical characters of morphine 
and its compounds, of codeine, narcotine, meconic acid, etc., place ourselves 
in position to see the significance of the appearance the slide presents, and to 
identify any crystalline principles which may be present. Nevertheless, even 
in the absence of very accurate knowledge, any one who will make a few ex¬ 
periments for the sake of practice, will soon be able, by observing the pre¬ 
sence or absence, the abundance or scarcity, of certain forms of crystals easily 
seen in typical specimens, to pronounce with little hesitation on the quality 
or genuineness of samples of any of the ordinary preparations of opium. 
Before proceeding to speak of the opiates which have come under our 
examination, it may seem necessary to say a few words on the forms assumed 
by the various opium principles and the physical characters their crystals pre¬ 
sent. This, together with certain drawings we have made carefully from spe¬ 
cimens, will afford a key to our further remarks. 
In the first place:— 
Morphine .—The pure alkaloid crystallizes in right-rhombic prisms often run¬ 
ning into needles. The single crystals have but little effect upon the polar¬ 
ized ray, but where the solution has been concentrated (as from alcohol), and 
the acicular crystals are much overlaid, they present a good deal of colour. 
(Plate I. fig. 1.) 
It is exceedingly difficult to say in what condition morphine exists in opium ; 
we are well aware that it lias been set down as meconate, with a smaller per¬ 
centage of sulphate, but we have reason to suspect that sulphate is present to 
a larger extent than is generally supposed. The messing and manipulation 
which all kinds of opium appear to undergo before they reach this country,, 
renders the belief which is suggested by other circumstances, that a portion of 
