Egg survival in immature rat ovaries grafted after freezing and thawing

Immature rat ovaries grafted subcutaneously after freezing and thawing show a heavy loss of eggs. A number of variations in the freezing technique have been tried but have not led to any substantial increase in egg survival. Similarly treated ovaries may show a wide variation as grafts. Methods for estimating and comparing the effects of different freezing techniques on the eggs have been worked out.