Abstract
Histological changes on the development of the adrenal glands of domestic fowls (white leghorn, female) were studied.
The cortical tissue, arising from the splanchnic mesoderm is seen in 3-4 days old chick embryos and the medullary tissue, coming from certain cells of neural crest is noticed in 5 days-old embryos.
The area percentage of the medullary tissue to the whole adrenal gland in several sections is 4% in the 10 days-old embryo, 20% in the 1 day-old chick, 32% in the 50 days-old chick and about 33-40% in the hen.
The nuclear volumes of cortical cells are already relatively large in the embryo and do not increase so much, while those of medullary cells become larger with high speed in the embryonic days as well as in the early days after hatching.
Sudanophilic substances in the cortical tissue appear in the 10 days-old chick embryo and increase in number and size with the days. The Nile blue reaction is weakly positive in 11-12 days-old embryo and becomes stronger thereafter.
Silver granules reaction indicating vitamin C is seen in the cortical and medullary tissues of the 11 days-old embryo. In this stage, however, the granules in the cortical tissue are very few and are scattered in the whole tissue, and increase in number gradually in the later embryonic days and remarkably after hatching till about the 30th day. In the medullary tissue, these granules are seen always very scarce in both the embryo and the hen.
The chromaffine reaction of the medullary cell is positive in the 10 days-old chick embryo and becomes stronger with the increase of days till about 30 days after hatching.
