ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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rapidly from the C0 2 given out by the snail ; B as rapidly darkens and 
reddens ; while C remains unchanged. 
Microchemical Reaction for Nitric Acid.* — Mr. J. L. C. Schroeder 
van der Kolk has for several years used the following test, which is 
somewhat similar to that recently proposed by R. Brauns, j The sub- 
stance to be tested is placed with a drop of sulphuric acid in the hollow 
of a glass slide, and from the cover-glass hangs a drop of barium hy- 
droxide solution ; when nitric acid is driven off, typical crystals of 
barium nitrate appear in the drop on the cover-glass. As the substance 
tested does not come into contact with the barium solution, the presence 
of sulphates, phosphates, &c., does not affect the result. 
Dead-Black Surface oil Brass. J — To 2 grains of lamp-black in a 
saucer add, says Mr. L. A. Wilson, just enough gold-size as will hold 
the lamp-black together, and mix thoroughly. Dip a lead pencil into 
the gold-size, and the right quantity will be obtained; add drop by 
drop. After the lamp-black and size are thoroughly mixed and worked 
up, add 24 drops of turpentine, and work up again. Apply the mixture 
with a camel’s hair brush. When thoroughly dry, the brass will look as 
if it had just come from the optician’s hands. 
Laboratory Notes. — Prof. K. Goebel § recommends the follow- 
ing objects for the purposes specified : — The leaves of Elatostemma sessile 
for the exudation of drops of water. Klugia notoniana for the forma- 
tion of the embryo within the ovule. The protoneme of Mosses for the 
formation of starch out of sugar. The germination of the protoneme 
from the spore can be well followed out in Fanaria Jiygrometrica. 
Herr M. Baciborski || finds the epidermal cells of the perianth- 
leaves of cultivated species of Albuca favourable objects for observing 
the formation of crystalloids in the vacuoles within the endosperm. No 
fixing or staining of the object is necessary. The elaioplasts can also be 
demonstrated in the same cells. 
Reversible Mailing Cases.lf — Messrs. Bausch and Lomb have 
brought out new mailing cases for microscopical slides. All the pieces 
are similar and interchangeable, thus avoiding the use of “ tops ” and 
“ bottoms.” An ample depression in the face of each piece allows the 
stowing of a slide with a large cover. Any number of slides and cases 
may be adjusted and piled one above the other, or one slide may be held 
securely by simply reversing one piece of wood. 
* Neues Jakrb. Mineral., i. (1897) p. 219. 
t Cf. this Journal, 1896, p. 687. X The Microscope, v. (1897) pp. 43-4. 
§ Flora, lxxxiii. (1897) pp. 74-5. || Tom. cit., p. 75. 
Journ. New York Micr. Soc., xiii. (1897) pp. 41-2 (2 figs.). 
