At the blister stage, the integrity of the membrane is still
intact and the changes of nuclear morphology may be
observed with florescent dyes. However this stage does
not last long and the integrity of the membrane becomes
impaired within minutes. Normally no dye is needed in
order to observe cells with the phase contrast microscope,
however as mentioned above the phase contrast microscope
may be used with florescent dyes as well at the
same time. By doing so, the phase contrast images and
the fluorescent images overlap and gives detailed information
of both nucleus and the cell membrane.