How to fix injected embryos ?

[Sidney B. Cambridge]

I am in the process of learning how to fix and antibody-stain injected
embryos. All of the protocols I found call for fixation of the embryos
while being attached to the coverslip. Besides wondering if there isn't
any other way of fixing, I can't figure out how exactly the coverslip is
placed in a biphasic solution 
(PEM/heptane) ????? Can anybody help me ?
Thanx in advance.

Cheers,
Sidney   (sc6c at andrew.cmu.edu)