Lydia M. Dewitt 201
The bands of cells follow the arrangement of the blood-vessels,
but I failed to find any arrangement of blood-vessels or cords
of cells which I could regard as characteristic for the species.
In some sections, a larger vessel may be seen entering at one
end of the area and passing through the center of the island,
dividing it into two more or less equal portions; smaller
branches passing off from the sides of this main vessel subdivide
each half into larger or smaller compartments, giving a figure
not unlike the figure and description given by Flint of the ar-
rangement of the connective tissue in the human areas. Very
little or no connective tissue, however, accompanies the vessels.
In other sections, the vessel enters at one side soon dividing into
numerous larger branches, which pass obliquely through the
area in every direction, giving off many secondary branches
which frequently anastomose by means of true capillaries.
The capsule, if such it may be called, is very delicate, and the
walls of the insular ca-
pillaries seem to rest
directly on the epithelial
cords. When some
shrinkage has taken X
place, however, the capil-
lary occupies the center
of a space which sepa-
rates it from the epithe-
lial cords, and in prepa-
rations well stained with
Mallory's connective-tis-
sue stain, delicate sheaths 3
of connective tissue are
seen to surround the ' · 4
blood-vessels; delicate
lines of blue outline the
cells, while a very thin
capsule of connective Fig. 2.-Area of Langerhans from pancreas
tissue separates the area of guinea-pig. Section through center of area
from the pancreatic acini. x 20.
The amount of connective tissue in the areas is so much less than