58 
Selected Articles. 
tals may be obtained and is this way nearly all the bi-malate 
may be separated. The salt thus procured will often be 
slightly tinged with colouring matter, in which case it should 
be re-dissolved in hot water and crystallized anew. It is 
then perfectly pure. 
When the crystallization of the bi-malate has been rapid the 
mass presents the pure and shining white of the sulphate of 
quinine. When more slowly conducted, hexagonal prisms of 
the most beautiful proportions are obtained. The largest of 
these have generally two of their parallel faces much broader 
than the rest, so that when placed upon any smooth surface 
they have the appearance of rectangles, slightly bevelled at 
the edges. In the salt suddenly crystallized, the crystals are 
much more slender, and are perfectly regular hexagonal 
prisms with bevelled extremities. They are frequently in 
pairs crossing at right angles, and in groups formed of se- 
veral of these pairs. The variety of proportions among the 
different crystals and the exact symmetry which each pre- 
sents are matters of very pleasing observation through the 
microscope. The great facility with which this salt crystal- 
lizes from the infusion of the berries, led me at first to doubt 
whether the acid contained in it was really the malic, for it 
would appear from the remarks of Berzelius and Thompson 
on the bi-malate, that hitherto it had not been procured in the 
crystalline form from the juices or infusions of plants. The 
former chemist in the fourth volume of the Traite de Chimie, 
speaking of this salt under the title of Sur-malate Calcique 
observes, "II resemble a la gomme par son aspect;" and 
again, "Ce qui vient d'etre ditne se rapporte qu'au sel tiree 
des plantes ; d'apres Braconnot celui qu'on prepare a l'aide 
de l'acide, cristallise en prismes hexagones." Dr. Thomson 
does not speak of it as crystalline, and states that "when the 
supermalate of lime is evaporated to dryness it assumes ex- 
actly the appearance of gum arabic." 
A very careful examination of the crystalline salt shows it 
to be a true bimalate, and I am therefore disposed to think 
that the uncrystallizable character of the bimalate procured 
