Abstract
Stated in the following are the findings of the varying stainings and the examinations of PAS and metachromasia applied on the collagenous, argentaffine and elastic fibers of the skin of 30 human fetuses during the period from the 2nd to the 9 th month of embryonation
1. Argentaffine fibers appear in the epidermo-dermal junction as early as in the 2nd month of embryonation. This author wishes to support the opinion to say that the generation of argentaffine fibers is influenced by the contact of the ectoderm and the mesenchymal tissue. The reticular fine argentaffine fibers which appear in the upper part of the dermal papillae, however, are considered to develop by different mechanisms.
2. Prior to the appearance of fibrous element in the dermis, PAS reaction positive granules appear in mesenchymal cells and the granules diminish in number following the appearance of fibers, in the dermis suggesting that mesenchymal cells are playing an important role in the fiber formation of human skin.
3. Findings of the present study confirmed the opinion to say that collagenous fibers are metamorphosed from the argentaffine fibers appearing in the lower layer of the dermis.
4. Elastic fibers begin to appear from the 7th month of embryonation.
5. Metachromasy was found to appear in the upper layer of the dermis from the 5th month of embryonation.
