1878. ] © The Serpent and the Ape. 225 
some mineral slices will prove to be very fragile on account of 
their thinness. Sections which are made of a rock material which 
needed a preliminary treatment with Canada balsam to make it 
firmer would break entirely to the smallest fragments in the 
attempt to remove them to another glass, and have therefore to 
remain on their original glass. Before covering them, the greatest 
care should be taken to free them entirely from any Canada bal- 
sam around the borders of the mineral section, and also from 
emery, which sometimes can only be detected by aid of a magni- 
fying glass. The re-mounted mineral slice, or the one which 
could not be removed, as stated above, is covered with a few 
drops of Canada balsam and laid again upon the warm slab till 
the balsam has obtained the required tenacity. A thin cover- 
glass, corresponding in size with the mineral slice is cleaned with 
alcohol and warmed; it is then taken up with a pair of forceps 
and dropped slopingly on the slice so as to exclude any air. The 
section is left on the warm slab till all air bubbles have disap- 
peared which may have been enclosed between the section and 
cover-glass; the latter is gently pressed upon the section and 
then allowed to cool. Care should be taken to place the mineral 
slice and cover-glass in the centre of the glass slide, which will 
contribute to a nice appearance of the finished preparation. The 
surplus of Canada balsam around the cover-glass is cleared off 
by brushing it with turpentine, then it is well rinsed with water 
and after being dried it should be labeled at once. The labels 
should be applied on both sides of the preparation and inscribed 
with the name and locality and geological group of the prepared 
material. It is well to number the sections and record them in a 
catalogue in which also a description of the most interesting and 
principal features of each mineral slice may be given, which will 
facilitate a future study of the section. 
:0: 
THE SERPENT AND THE APE. 
BY ARTHUR E. BROWN. 
Woa the purpose of observing the manner in which the feel- 
ings of curiosity and astonishment are manifested in the 
monkey, Mr. Darwin once introduced a snake into a cage con- 
taining a number of those animals, and the results of his experi- 
