42 SHINICHI MATSUMOTO 



B. PHAGOCYTIC PHENOMENON OF THE CORNEAL EPITHELIUM 



Though the experiments on this hne have not yet been com- 

 pleted, some interesting phenomena will be described here. 



It was noted in the course of this work, that not infrequently 

 in the preparations of cornea, where the pigment of the iris or 

 chorioidea was accidentally mixed with the epithelium, the cells 

 of the latter, originally not pigmented, took up the pigment, be- 

 coming gorged with it. This was easily demonstrable, but more 

 markedly when the pigment of the eye was finely teased and put 

 into the culture medium with the corneal epithelium. The cells 

 of the moving border, especially, took up the dark pigment 

 abundantly. 



That the melanin granules are really taken up in the cytoplasm 

 of cells, was clearly demonstrated in the preparations which were 

 first vitally stained with neutral red (fig. 3). That those pig- 

 mented cells were not the originally pigmented epithelium of eye, 

 accidentally mixed in the preparation, is beyond doubt. The 

 epithelial cells were able to take also melanin which was previ- 

 ously heated or boiled. 



.The arrangement of the pigment granules in the cytoplasm 

 was characteristic, resembling that of the neutral red granulations. 

 The cells of the basal layer were often abundantly packed with 

 the pigment, and those of upper layers were able to ingest it, too. 



If in the epithehal cells which are originally not pigmented, 

 abundant melanin is taken up, it is extremely difficult to distin- 

 guish them from the original pigment cells. 



The possibility of epithelial phagocytosis has been considered 

 by Riehl ('84); somewhat later, Rabl ('96) also took up the ques- 

 tion and found that the epithehum of adult salamanders (S. 

 maculosa) is able to take up cai^min injected subcutaneously. In 

 cultures of carcinoma and sarcoma, Lambert and Hanes ('11) 

 demonstrated that carmin granules are taken up by the cells. 

 Carrel and Burrows ('11) observed a similar phenomenon in cul- 

 tures of sarcoma. 



The melanin problem represents one of the most interesting 

 questions in dermatohistology and experimental dermatology 

 and is a much discussed subject. I should not go, of course, so 



