22 THE MICROSCOPICAL NEWS. 
long by 14 inch wide, into one end of which a piece of wire has 
been inserted and bent over to form a clip, the centre being covered 
with a circle of wz¢fe paper to form a light background. A piece 
of glass about 1 inch by 14 inches, to be used as a presser, is placed 
upon the glass and under the spring, and is kept apart from the 
slip by several folds of paper about the thickness altogether of 
the fly’s head. The head, with the eyes uppermost, and the tongue 
protruded towards the right hand, is then placed in a drop of acid 
under the edge of the presser and held there, and, if necessary, the 
tongue forced to protrude further by a slight pressure of the fore- 
finger of the left hand. While in this position the expander, a 
piece of glass 1 inch long and of an inch wide, to the under side of 
which a small covering glass has been fastened by brown cement, 
and having a piece of paper by which to hold it gummed to the 
top (Fig. 15), is used to force the lobes of the tongue backwards, that 
is towards the left hand, and downwards into the required position. 
The Palpi, which will usually be found lying against the head, may 
then be arranged by means of a stiff bristle, and the head laid 
aside for three or four days to set. 
Mounting.—After cutting away the head, transfer the tongue 
which must be kept the same side up, to a drop of fresh acid on 
the centre of a clean glass slip. This may be done by pushing it 
on to the end of a quill which has been bent a little at the end, to 
form a kind of a spoon. Apply balsam at the right-hand side of 
the cover-glass, and drain off the acid by holding a piece of blotting 
paper to the opposite edge. If any cloudiness appears, warm the 
slide a little. A light slip may then be put on, and the slide put 
aside to harden. No needles should be used in any part of the 
process. 
PROFESSOR ABBE’S TEST OBJECTS. 
T the October meeting of the Royal Microscopical Society, Mr. 
Ingpen stated that, even amongst those thoroughly familiar 
with the use of the highest powers, very few would be found capable 
