--- "April E. Monchik"  wrote: > I am a
technician in a research institution core facility.  My 
> question pertains to paraffin sectioning.
> When I cut rat heart tissue it looks like the paraffin has not 
> infiltrated.  There are many holes in the tissue.  This happens
> even 
> when I use a knew knife.

Steve Machin answers:

If the surface of the cut block is hard then it isn't likely to be
poor processing.
Get a lens and look at the surface of a trimmed in block for tiny
pits.  If they are there then you are trimming the block too roughly
before cutting.

If the surface is slightly white and a little soft then it may be
poor processing.

Smell the surface of the block after trimming but before cutting.  If
you can smell xylene then increase the wax times.  If increasing the
wax times doesn't work then increase the alcohol times.

Best Wishes
Steve Machin UK

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