416 
PHARMACEUTICAL MEETING. 
Atropine and Daturine .— On account of the great similarity between these 
two substances, it will be as well to speak of them together. Atropine is de¬ 
scribed by Gmelin as partly volatilizing. Pereira says that daturine and atro¬ 
pine both melt at 190° F. without losing weight or undergoing decomposition ; 
at a higher temperature both are decomposed. Atropine and daturine present, 
when submitted to heat, precisely similar features; they melt and remain per¬ 
fectly colourless, and sublime in perfect crystals ; the two sublimates closely 
resembling each other. 
Rhein is thus spoken of by Pereira :—“ Heated, it evaporates, emits yellow 
fumes, which condense and form yellow flocculi, and at the same time a part 
becomes decomposed.” In the edition of Thomson’s ‘ Vegetable Chemistry,’ 
before mentioned, is the following :—“ Rhein may be sublimed in a yellow 
smoke, which when condensed is a yellow powder, sometimes crystallized.” It 
sublimes very easily, the crystals mostly appearing as thin plates, with pointed 
ends, and sometimes curved. It sublimes before and after melting. 
Coumarin .—The odoriferous principle of the tonquin bean also sublimes, but 
a low temperature is requisite to obtain it in crystals. 
I have to thank Messrs. Macfarlan, of Edinburgh, for all the alkaloids of 
opium, and Messrs. Huskisson and Messrs. Hopkins and Williams for a quantity 
of alkaloids and active principles, many of which I have been unable for want 
of time to work at. 
iff the sublimates are mounted as permanent objects, it is necessary that 
they should be mounted dry. The ordinary method of doing this would most 
probably be to use gold size, but the evaporation of the spirit from this in 
drying, in many cases, partially dissolves the crystals. For this reason it is 
better to use asphalte varnish. 
I must acknowledge that this paper is to a great extent vague and indefinite; 
to do the subject justice would take as many months as I have given of weeks. 
As it has excited no little interest, I thought that any information, however 
scanty, that would tend to throw light upon it, would be acceptable to many, 
and it is with this idea that I have ventured to bring these remarks before you. 
Dr. Guy said the Society would feel very much obliged to Mr. Waddington, 
if they valued his labours as highly as he did. As far as they had gone they 
had confirmed, and more than confirmed, the results at which he had himself 
arrived ; but the object which Mr. Waddington had had in .view appeared to 
have been rather to procure very fine and perfect specimens of crystals of the 
alkaloids than to do that which he had himself aimed at, viz. to verify the 
statements of Helwig,—to substitute what he supposed to be an improved method, 
and to apply heat as any experimenter operating for the first time would be 
likely to do. He did not enter at first into the question of the particular tem¬ 
perature at which the best results would probably be obtained. The specimens 
exhibited by Mr. Waddington were very fine : indeed, in some thousands of 
experiments he (Dr. Guy) had only obtained a few specimens so fine as those 
now shown. Mr. Waddington was, no doubt, perfectly correct in what he had 
said as to the importance of attending to the temperature, and he believed 
the best results were always attained when the temperature of the superim¬ 
posed glass was made to approach nearly to that of the surface from which the 
alkaloid was being sublimed. And what was true of the alkaloids was true also 
of arsenious acid,—they could not get good specimens without having the su¬ 
perimposed glass of a tolerably high temperature. He wished, however, to say 
a few words on a point which had not been mentioned by Mr. Waddington, 
and to show how extremely delicate this mode of procedure was. It was thought, 
