362 The American Naturalist. [April, 
in imbedding and sectioning a considerable number of objects as one; 
and above all when many objects much alike are to be imbedded, there 
is no danger of confusion, since each one is plainly marked with its 
appropriate number. 
a oe e  * *& * o 
II. Asevery one knows, itisag t tund : 
a large number of objects that tend to roll about into undesirable posi- 
tions. Itis often necessary to mount each one separately and then roll 
it about at great risk, till it is is just where we want it. And after all 
it is impossible to roll some things into place. I have used a modifica- 
tion of the method described above in mounting large numbers of 
objects under one cover, in perfect order, and in any desired position. 
In mounting the eggs of Limulus, or heads of insect embryos, etc., 
I construct a cell of the requisite dimensions, and place in it small 
drops, close together in rows, of the thick collodion and clove oil. An 
egg is taken out of the clove oil, drained, and placed in a drop of 
lodion in the desired position. A great many eggs may thus be 
arranged like serial sections under one cover glass. Before adding 
the balsam, the slide is immersed in turpentine, which serves to wash 
away the clove oil and leave the eggs firmly fixed in the collodion. 
The only precaution necessary is not to use too much collodion. It 
is surprising to find the small amount necessary, and the firmness with 
which the objects are held by it in place. 
I have recently used, with a class of beginners, the above method of 
imbedding, with satisfactory results—merely as a matter of convenience 
in manipulating small objects easily soiled or broken in handling. 
Any glazed paper, or glazed tracing cloth will do, provided the collodion 
and clove oil is thick enough. The raised ribs may be replaced by fine 
black lines drawn with a soft pencil. These lines like the numbers 
are transferred to the paraffine when the paper is removed. 
WiiraM Parren, Hanover, 
N. H. 
aR A E dese 
