POSTFOLLICULAR DEVELOPMENT OF THE FETAL THYROID-GLAND IN GOAT

Postfollicular development of the thyroid gland was studied in 54 goat foetuses ranging from 30 to 150 days in age. The gland attained bilobed character in 30-day old foetuses. The follicles containing PAS-positive colloid were, however, observed at day 60. Their relative proportion and amount of colloid in them increased with age of the foetuses. The percentage of follicles filled with thin basophilic colloid to the total follicles was highest in subjects of 125-150 days of gestation. Majority of the follicles in these foetuses were lined with simple columnar epithelium and showed increased PAS-positive reaction in supranuclear zone. The vacuoles at periphery of the colloid were also evident at this stage.