Margaret,
There was a paperback scientific book published in the 60's that dealt with 
the subject of shrinkage. I think it was called "Cytological Technique" by 
Bruce Casellman. I may even have it stashed away somewhere at work.

The author measured the rate of penetration and shrinkage of different 
fixatives. I seem to remember he also used blocks of gelatin as some of his 
model "tissue".

This book would be a good place to start any study on shrinkage.

Mike Titford
USA Pathology
Mobile AL