312 
A New Trematode 
in the form of a fairly broad highly refractive and homogeneous band with 
a faintly marked concentric stratification. This layer probably represents the 
product of secretion of the parasites themselves. 
(2) The second layer is well developed in some places, while absent in 
others. It consists of weakly straining granular masses derived from broken 
up cellular elements (Fig. 8,6.) and showing elongated cavities corresponding 
to the outlines of fatty acid crystals dissolved in the process of treatment of 
the preparations. In some places, between the cysts, the granular layer fuses 
directly with the masses of disintegrated and necrotic pancreatic lobules. The 
absence of transitional forms between these two structures indicates, however, 
that the granular layer could not possibly be derived from the necrotic 
pancreatic lobules. It is more likely that the elements of this layer represent 
the necrotic cells of an inflammatory exudate accumulated around the parasitic 
cyst. 
(3) The third layer, which is the broadest, consists of compact fibrous tissue 
with the fibres arranged concentrically around the cyst. This layer is divided 
into two strata: (a) the inner and (b) the outer. 
(a) The inner stratum is thinner, more compact, with the fibrilar structure 
not clearly defined (Fig. 8, c.) and it stains strongly but diffusely with iron 
haematoxylin. Between the fibres of this stratum are seen elongated nuclei 
(belonging to cellular elements) in a pycnotic state. This stratum seems to 
be composed of fibrous connective tissue undergoing necrosis and probably 
impregnated with lime. 
( b ) The outer fibrous stratum has the same structure as the inner one but 
its fibrilar structure is well defined; the nuclei of the included elongated cells 
show no pycnosis, nor do they stain diffusely with iron haemotoxylin; they 
have the appearance peculiar to the nuclei of compact fibrous connective 
tissue cells. 
Thus the fibrous capsule which surrounds the parasite is quite similar to 
those produced in other animals around foreign bodies as the result of inflam¬ 
matory reaction. 
4. Externally to the fibrous layer, there is a more areolar connective 
tissue of a lamellar character, which passes directly into the connective 
tissue stroma of the pancreas. It contains a fair number of cellular elements 
and many pigment cells (Fig. 8, e.) arranged in groups, all elements being 
disposed parallel to the layers of the fibrous capsule. The pigment cells may 
be either stellate or polygonal whilst the very minute pigment granules 
enclosed in them, which are of a deep-black or yellow-brown colour, completely 
obscure the cell nuclei. In the outer portions of the areolar layer, as well as 
between the separate adjacent lobules of pancreas, in addition to the stellate 
pigment cells with black granules, are found groups of smaller, partly polygonal 
cells, with yellow-brown granules. The latter are sometimes found irregularly 
distributed in the cell protoplasm in the form of large clumps. These cells, 
differing considerably from other pigment cells, have probably another origin. 
