On the size of Hassall's corpuscles in human fetuses.

The areas of prevailingly solid (SHC) and prevailingly cystic (CHC) Hassall's corpuscles in the thymuses of both male and female fetuses 16-39 weeks old were established. The results show that the mean areas of the Hassall's corpuscles increase with fetal age, with the greatest difference between the 16-19 week and 20-23 week age groups. The data indicate that the thymus represent an organ showing a developmental pattern similar to other organs like the spleen's relative growth in human fetus, whose functions are different during the fetal period, being necessary to study its growth in distinct short periods to determinate differentials growth coefficients.