414 
PHARMACEUTICAL MEETING. 
some time, and it gradually gave way to a crystalline sublimate, which slowly 
spread over the whole surface in flowery patterns. Upon leaving it still longer 
the quinine began to sublime in long filaments (1 can hardly call them needles), 
and wherever a piece of dust formed a nucleus, the sublimate crystallizing 
round it assumed a more definite shape. When the slide was removed the 
sublimed quinine had completely filled the glass ring, and could be lifted off in 
a single flake. 
Quinidine is spoken of in Gmelin’s ‘ Handbook ’ as partly subliming. On 
account of the difficulty of obtaining this substance in a state of purity, I may 
mention that the quinidine here operated on was kindly given to me by Mr. 
J. E. Howard. It had been crystallized from ether and was absolutely pure. 
It was mixed with powdered glass, and heated in the usual way. The mixture 
soon became spongy and slightly swelled, the quinidine almost immediately 
commencing to sublime, the sublimate appearing as small globules; these 
gradually gave place to long crystalline masses, possessing little definite shape. 
The heat was now cautiously continued for two hours, during which these pieces 
broke up, and formed thin platy crystals, which in some instances were perfect, 
but generally, owing to the quantity of sublimate obtained, the crystals had 
little room to form. The same rule holds good in crystals obtained by subli¬ 
mation as in those deposited from solution, namely, that they form much more 
readily when a piece of dust or a hair affords them a nucleus. Some substances 
(notably quinidine) which have swelled by the heat, so as to touch the receiving, 
glass, have left very small fragments adhering to it, and perfect crystals have 
formed round such nuclei before any other part of the slide has shown a trace 
of crystallization. 
Cinchonine .—In an edition of Thomson’s ‘ Vegetable Chemistry,’published 
in 1837, cinchonine is spoken of as u volatilizing when cautiously heated, yielding 
a crystalline sublimate.” It is described in Gmelin’s ‘ Chemistry,’ as “ melting 
only when it begins to decompose, and volatilizing partly undecomposed also, 
as “ melting at 161° C. without loss of weight, and on further heating subliming 
partially in dazzling white needles.” By the method I have described cincho¬ 
nine may be sublimed very easily and without the least change of colour. It 
bears a considerable amount of heat, and sublimes in very perfect crystals. 
Cinchonidine. —Gmelin’s ‘ Handbook’ has the following:— U A slight sublimate 
is sometimes obtained in a glass tube, which consists, according to Winckler, 
of unchanged cinchonidine. I have found that it sublimes very rapidly, and 
has a great tendency to deposit on the glass, in curved lines, more or less crys¬ 
talline. Some little difficulty is experienced in producing perfect crystals, but 
by careful management they may be obtained without any change of colour in 
the original substance. 
Alizarine and Theine are well known to be volatilized by heat, and call for 
little remark. When alizarines mixed with glass and heated the colour is con¬ 
siderably increased, but the whole of the alizarine may be driven off, leaving the 
glass perfectly white. 
Murexide .—This substance requires a very, high degree of heat before any 
sublimate results. It should be placed on the iron plate itself, as sufficient heat 
can hardly be obtained if glass intervenes. The first effect is the production of 
concentric prismatic rings, which as the process proceeds spread over a larger 
surface, smaller rings being at the same time formed ; the deep red colour of 
murexide is now seen on the glass ; if heat is continued a kind of semi-crystal¬ 
lization is apparent of great depth of colour, requiring mounting in Canada 
balsam before it can be defined. This account of murexide must be considered 
unsatisfactory; a portion of it was evidently decomposed, as a black powder re¬ 
mained ; but the production of the murexide colour, and the pseudo-crystal¬ 
lization warrants the supposition that by more effective treatment a sublimate 
may be obtained. 
