b2 PREPARATION AND MOUNTING 
CHAPTER DEH: 
TO PREPARE AND MOUNT OBJECTS “ DRY.” 
Tue term “dry” is used when the object to be mounted is 
not immersed in any liquid or medium, but preserved in its 
natural state, unless it requires cleaning and drying. 
I have before stated that thorough cleanliness is necessary 
in the mounting of all microscopic objects. I may here add 
that almost every kind of substance used by the microscopist 
suffers from careless handling. Many leaves with fine hairs 
are robbed of half their beauty, or the hairs, perhaps, forced 
into totally different shapes and groups; many insects lose 
their scales, which constitute their chief value to the micro- 
scopist ; even glass itself distinctly shows the marks of the 
fingers if left uncleaned. Every object must also Le 
thoroughly dry, otherwise dampness will arise and become 
condensed in small drops upon the inner surface of the thin 
glass cover. This defect is frequently met with in slides 
which have been mounted quickly; the objects not being 
thoroughly dry when enclosed in the cell. Many cheap 
slides are thus rendered worthless. Even with every care 
it is not possible to get rid of this annoyance occasionally. 
A good plan is to fix the covers on to the cells temporarily 
by dropping on two sides of them a composition of equal 
’ parts of wax and resin: this allows of the easy removal of 
the cover at any time, while the object thoroughly dries 
and is protected from dust and damage. © 
For the purpose of mounting opaque objects “ dry” 
discs were at one time very commonly used. These are 
circular pieces of cork, leather, or other soft substance, from 
one-quarter to half an inch in diameter, blackened with varnish 
