CELLS LINING THE PERITONEAL CAVITY 401 
describes a concentration of the dye-granules near the nucleus, 
but suggests that this is due to the greater amount of cytoplasm 
in that region, and he intimates that there are as many granules 
elsewhere in relation to the amount of cytoplasm. ‘The gran- 
ules, which he found, were always small and evenly distributed 
without accumulations in any particular areas, or irregular 
clumping as has been found in the clasmatocyte. His plate 
(1) gives a most interesting comparison between the immense 
amount of carmine which has been stored by the clasmatocytes 
and monocytes, and the sparse granulation of the serosal cells. 
On the other hand, the fibroblasts show amounts of carmine not 
very different either in amount or distribution from that of the 
mesothelium. Kiyono thinks that his work with vital dyes 
indicates a very definite and close relationship between the 
serosal cells and the fibroblasts, though he finds no actual transi- 
tion between the two cell-types. 
Evans (715) has also described the sparse granulation of the 
serosal cells, noting that the fine granules of dye were concen- 
trated around the nucleus, but his descriptions are very brief 
and do not indicate whether or not he agrees with Kiyono in 
regard to the more general distribution of dye-granules throughout 
the cytoplasm. 
Schlecht (’07) also describes the peritoneal mesothelium as 
taking vital dyes, but does not differentiate very sharply between 
the surface-cells and connective-tissue cells, which probably 
also include some true clasmatocytes. His observations are 
not very exact with regard to the serosal lining cells, but are 
sufficiently so to indicate that there are some vital dye-granules 
to be found in the serosal mesothelium. 
Tschaschin, on the basis of his-studies with vital dyes (713 a) 
and on experimental inflammations (’13 b), has concluded that 
the serosal lining cells constitute a specific group, having no 
relationship with the connective-tissue elements. 
Evans and Scott (20, p. 47) have referred to the subject of 
the specificity of mesothelial cells as distinct from fibroblasts 
and clasmatocytes in their monograph on the connective-tissue 
cells. They agree entirely with Tschaschin in considering the 
