412 R. S. CUNNINGHAM 
further around the nucleus, until, in many cases, in sections, 
granules of dye were found in either or both of the supranuclear 
and infranuclear zones of the cells. With such increased amounts 
of dye administered, the cell-body increased considerably in 
thickness usually throughout the entire length, though a supranu- 
clear bulge was occasionally present. This arrangement was 
constantly found in most of the cells, but there was a small 
proportion in which certain characteristic variations appeared. 
In some cells the location of the primary concentration was be- 
tween the center of the nucleus and the pole of the long axis; in 
such cells the extension of the mass led to considerable irregu- 
larities in the relation between the nucleus and its cap of blue. 
Some of these caps extended around or partly around the pole 
of the nucleus in an irregular fashion. Again, a few cells were 
noted in which two localized aggregations were situated on oppo- 
site sides connected by arms of blue extending around the nucleus 
from one to the other. These double caps were found on the 
two poles as well as on the two flattened sides of the nucleus, 
although they were more numerous in the latter location. Again, 
it was found that the lateral mass had extended almost entirely 
into the infranuclear zone and had produced a reaction somewhat 
similar to that seen in the germinal epithelium of the ovary. 
Finally, it must be noted that the lateral location of the dye- 
mass, extending a fine outline of granules around the nucleus to 
form the typical perinuclear rosette, may, I think, be considered 
as the one most striking characteristic of the splenic mesothelial 
cells of the rabbit when vitally stained with trypan blue. 
Turning now to the results obtained with the intravenous 
administration of carmine, the cells of the splenic mesothelium 
were found to be equally as characteristic as when stained with 
trypan blue. In the early stages the carmine was found dis- 
tributed in the usual sharply localized area just lateral to the 
center of the nucleus and always superficial to it. As the amount 
of dye was increased, the area extended more and more on all 
sides, sometimes in a regular fashion, sometimes with fine lines 
and a few detached granules; figures 6 and 7 illustrate two stages 
in this progressive increase. ‘The perinuclear rosette was some- 
——— — 
