THE STORY OF THE RED BLOOD CORPUSCLES. LAT 
mals. In general appearance and structure they resemble 
lymphatic glands, the essential difference being that the 
former contain sinuses filled with blood. In some specimens 
the lymphoid tissue is very abundant, aud these often cannot 
be distinguished from lymphatic glands by the naked eye. 
In others the blood sinuses are of comparatively large size, 
and may even occupy the bulk of the gland. Such 
specimens can be distinguished by their red colour, and may 
even be quite conspicuous, as is the case in the sheep, where 
they form a striking contrast to the fat in which they are 
embedded. 
When a section of a hemolymph gland is examined 
under the microscope, the general arrangement of its 
structures is what is shown in the diagram, The parts of 
the gland which we are specially interested in at present are 
the blood sinuses. If these are examined under a high 
power, it will be found that the blood contained in them 
differs from ordinary blood, in that cells of the white corpuscle 
class are more numerous. In the case of animals like the 
sheep, where the glands are abundant, and the sinuses of 
large size, this difference may not be very marked; but in 
the case of the dog, whose hemolymph glands are few in. 
number, various kinds of cells may be exceedingly abundant 
in the sinuses. Among these cells, lymphocytes, eosinophile 
cells, and the ordinary wandering leucocytes may be 
recognised ; but the cells which are most noticeable, both 
from their size and from their numbers, are those usually 
designated hyaline cells. These cells have a large amount: 
of protoplasm. They are amceboid and phagocytic, and their 
form varies greatly. Very frequently inclusions of various. 
kinds are present in the protoplasm. The most common of 
these are red corpuscles, which are recognisable by 
their size and shape, and their staining reactions. Some- 
times twenty or thirty red corpuscles may be seen in a 
single hyaline cell. 
Fragments of nuclei in various stages of degeneration, 
and pigment in the form of minute granules or of large 
masses, may also be present within the cells, 
In the case of the dog, the sinuses are sometimes almost 
completely blocked by these hyaline cells, so numerous do 
