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PROFESSOR POUCH Et. 
muiiication between the afferent and efferent vessels. If at 
certain places these channels are definitely closed in, they 
sometimes open directly into the follicular substance ; in short, 
there is really no valid distinction to be drawn between the 
two tissues wliich are described as forming the Malpighian 
corpuscles, the lacunar tissue, and the follicular tissue. 
Therefore the following may be taken as a plan of a Mal- 
pighian corpuscle. On the lymph paths proper (lacunar 
tissue) are arranged certain caecal prolongations (follicular 
tissue), which are closed only at the periphery, but open on 
the other hand into the paths where they are continuous 
with them, by lacunae, which are here large, but get narrower 
and narrower towards the bottom of the caeca. 
Beyond the point of insertion on the lymph path the 
caecum is definitely bounded, and bounds in its turn the 
lymph path, or, in other words, the regions of lacunar tissue. 
In these caecal prolongations, as well as on the walls of the 
trabeculae of the so-called lacunar tissue, certain cells pro- 
liferate, and masses of cells are seen developing in them 
comparable to the nuclei of origin of the leucocytes, and 
which are evidently destined to fall into the lymph current, 
and form the latter. But sometimes these same cells, 
especially those in the lacunar tissue, undergo a different 
development. The protoplasmic body of the cell becomes 
rounded, and presents, along with other granulations of un- 
known nature, four, five, or six large granules, sometimes 
almost polyhedral, of a substance having all the characters 
of hsemoglobin. These granules have been constantly taken 
for hsematids in the course of formation, or for haematids 
collected together in cells to which amoeboid movements 
have been attributed, although no one has ever proved their 
existence, forgetting that the ultimate origin of the haema- 
tids thus observed in contact with the cells in question has 
yet to be explained. 
The interpretation of this phenomenon seems simple 
enough. Haemoglobin is not a special product of haema- 
tids ; it also occurs in the leucocytes of Semmer. The large 
granules of haemoglobin found in the cells of the lymphatic 
glands certainly do not originate elsewhere, and, moreover, 
are not simply haematids absorbed by the cells of the no- 
dules, just as they are not developing haematids. The 
presence of these granules of haemoglobin always has the 
effect, when they are abundant, of giving the tissue of the 
Malpighian corpuscle a reddish tint, and even a decided red 
colour, if the cells so altered are very numerous. We 
shall see presently to what errors tliis modification of the 
