534 GENCHO FUJIMURA 



though the preparations I have are still very poor to prove this 

 positively. However, the fact that, as mentioned above, lipoids 

 have their origin in very small granular bodies and that 

 plastosomes considerably decrease in quantity as the cell grows 

 in size and therefore its functions are promoted (please re- 

 fer to figs. 13 to 21), cannot but be taken for having proved 

 that plastosomes, owing to their quantitative relations, take 

 part in the lipoid formation and, if this deduction be practicable, 

 it would follow that the large group of plastosomes which 

 makes its appearance in an especially limited section, as is 

 seen in figures 3 and 9, should not be without significance for 

 the new growth and supply of lipoids. In short, the phe- 

 nomena of secretion of Langhans' cells, in general, are not very 

 active and yet the cells in the Langhans' islets are somewhat 

 different, and it seems the functions are very active in this 

 part, so much so as to make it a feature of these cells that they 

 present a very large and highly vacuolar formation (figs. 21, 

 22, and 26). 



Since the Langhans' cells always have on the surface a com- 

 paratively conspicuous border membrane, there is no alterna- 

 tive for the contents of vacuoles, viz., secretions, but to pass 

 through this membrane and be drained into the villous tissues, and 

 they are therefore possibly bound to be ultimately absorbed on 

 the side of the embryo. However, since the part like the Lang- 

 hans' islets where the functions are necessarily very active is, 

 as is well known either mostly wrapped up in the decidual 

 tissue or exists within the intervillous spaces, floating directly 

 in the mother's blood, it is possible that the secretions coming 

 from such a place are absorbed on the mother's side. More- 

 over, the large number of vacuoles which is found in a part 

 where the Langhans' cell layer comes in touch with the syncy- 

 tium cell layer as in figures 9 and 12, judged from the position 

 they occupy, has been temporarily denoted by me as forming 

 secretions of the syncytium layer and so described in the 

 previous paragraph; however, I am afraid nobody can say for 

 certain that it is so. If we suppose that the secretions are 

 brought forth by the Langhans' cells, who may say they will 



