181 
and the chemical and physiological properties of the alkaloid 
that it contains are, therefore, sufficient to show that it is 
nearly allied to Strychnos Nux vomica ; but they are also 
sufficient to distinguish it from that plant. 'It will be inte- 
resting to see how far this opinion is confirmed when an 
opportunity is obtained for examining its floral structure, and 
thus ascertaining its affinity with certainty. 
In the parcels of akazga received there were a few leafless 
stems, which were found to contain an immense number of 
sparkling crystals beneath the bark. These stems also differ 
from the others in the exterior of the bark having a smooth 
appearance. A microscopic examination of the stem revealed 
the following characters : 
The wood has the same general structure as that already 
described as belonging to akazga, the wood-cells being greatly 
indurated, and the medullary rays being arranged in the same 
manner. The cross-plates of parenchyma in connection with 
the dotted ducts are, however, shorter in cross-section, hardly 
extending beyond the immediate neighbourhood of the dotted 
ducts. 
The pith contains very few indurated cells. 
In the inner oortion of the bark, and also in the longitu- 
dinal cylindrica. tracts of delicate parenchyma traversing the 
wood, a number of prismatic crystals, terminated in domes, 
occur. These are arranged longitudinally to the stem. 
There is no layer of indurated parenchyma in the bark. 
Guided by these characters, Professor Dickson — who had 
kindly interested himself in the subject — pronounced that 
these were not stems of akazga. Dr. Fraser was at first 
unwilling to adopt this opinion, but a physiological and 
chemical examination has now convinced him of its correct- 
ness ; for the bark of these stems is perfectly inert, and the 
alcoholic extract that is obtained from it does not possess the 
well-marked chemical reactions of that obtained from 
akazga. 
On the Staining of Microscopical Preparations. By Dr. 
W. R. M‘Nab. The author enumerated a large series of 
experiments he had made by staining certain microscopical 
structures with acetate of mauvine and Beale's carmine solu- 
tion. He showed that by means of staining, the high powers 
of the microscope can be used to bring out points of structure 
not easily demonstrated without being so treated. The pro- 
cess of staining does not seem to be attended with any great 
difficulty, and the author believes that very important results 
may be obtained by careful study of its action on germinating 
plants. 
