ON THE SUBLIMATION OF THE ALKALOIDS. 
13 
sublimates to that of alkaloids which afford such sublimates, at least occasion¬ 
ally. If to the alkaloids which give characteristic sublimates we were to add 
those which, though not characteristic in form, give peculiar reactions, we 
should probably find that more than half of all these substances are recognizable 
through the form of their sublimates, or through their reactions with liquid 
tests. Sublimation, then, may be safely added to the list of those properties of 
the alkaloids which go to make up a complete description. 
But it may be asked :—Is this property of sublimation by heat and deposit 
on cooler surfaces the exclusive possession of a small group of metallic poisons 
(such as arsenious acid, calomel, and corrosive sublimate) and the alkaloids and 
analogous active principles? We already know that an animal product, can- 
tharidine, sublimes unchanged, and deposits itself in very distinct crystalline 
forms ; and that camphor sublimes at common temperatures, and settles on glass 
bottles and shades in beautiful octahedral crystals ; and I may add, as a sufficient 
present answer to the question, that I obtain crystalline or ocher well-marked 
deposits from urea, uric acid, hippuric acid, alloxan, and uramile ; and from ben¬ 
zoic, tannic, iodic, and tartaric acids, these being substances which I happen to 
have at hand. 
It may, therefore, be safely affirmed that sublimation and deposit on cooler 
surfaces (often in forms eminently characteristic, and with changes of form and 
colour not less striking,) are properties not only of arsenious acid, corrosive subli¬ 
mate, and a small group of inorganic substances to which it was first applied, and 
for which I devised the simple procedure already described, but also of a vast 
number of organic products, among which the alkaloids and active principles 
constitute only one class. 
There is still one more preliminary question, to which Dr. Helwig does not 
refer, but which is both interesting and important; namely, do the salts of the 
alkaloids yield sublimates as well as the alkaloids themselves? An answer to 
this question, sufficient for my present purpose, is furnished by the statement 
that the acetate, nitrate, hydrochlorate, sulphate, and phosphate of strychnine 
afford sublimates, and that one such sublimate from the acetate is not distin¬ 
guishable fr^m a well-merked crystalline deposit obtained from the alkaloid 
itself. I also procured sublimates from acetate of morphia, from sulphate of 
atropine, and from the sulphates of quinine and quinidine. 
It appears, then, that these important preliminary results have been already 
arrived at:— 
1. That the test of sublimation is easy of application, and successful with 
very minute quantities of the alkaloids. 
2. That sublimates may be obtained not only from the alkaloids themselves, 
but also from deposits furnished by their liquid solutions. 
3. That the salts of the alkaloids yield sublimates. 
4. That the properties of sublimation by heat and deposit on cooler surfaces 
are common to a large number of substances both inorganic and organic. 
5. That as probably one-half of the alkaloids and allied active principles 
yield characteristic sublimates, sublimation ought to be admitted among the re¬ 
cognised properties of these bodies as a class. 
These propositions, however, are but the preliminaries of an inquiry which de¬ 
mands the utmost patience, care, and circumspection, and which, if I do not 
greatly mistake the indications I have already obtained, will add largely to our 
knowledge by many new facts, as well as by some corrections of statements 
too hastily put forward. 
In my next communication I shall endeavour to point out the precautions 
which we must observe if we would turn this newly-discovered property of the 
alkaloids to practical account. These precautions must be recognised and acted 
upon before we proceed to the examination of individual members of the class. 
