>I haven't tried it yet, but there is a product called Histogel, from 
>Richard Allen Corp., which one can use to encase tiny fragile 
>samples, then process and embed, without losing the orientation or 
>the sample. Their number is 1-800-522-7270, and they will send you a 
>free sample. It is similar to encasing a sample in agar, but better.
>Joyce

Joyce,

I have tried the Histogel, and it's quite nice for orienting small 
specimens for the desired plane of sectioning.  I've also tried agar, 
but it doesn't seem to infiltrate.  But Histogel infiltrates quite 
nicely.  After pre-embeding the emrbyos in Histogel, I then place the 
tiny Histogel blocks containing my properly oriented embryos in this 
screen device that latches, holding the tiny Histogel block snugly 
between to layers of mesh material.  The screen devices fit into your 
standard cassette.  I believe I got these screens from Mercedes 
Medical, 800-331-2716.

Karen in Oregon