structure of the brain and nerves , &c. 45 
Plate V. 
The human spleen of the natural size, from a man 48 years of 
age. The arteries and veins are injected with the same colour, 
showing that they run in pairs, enclosed in a common theca. 
Plate VI. 
Represents two sections of the spleen, one prior to macera- 
tion, the second after being in distilled water three days. 
Fig. 1. A transverse section of the same spleen, as repre- 
sented in PI. V. of the natural size. Upon immersing it in 
distilled water, the cells emptied themselves of lymph glo- 
bules ; and upon turning it over, the same thing happened to 
the opposite side. 
Fig. 2. A surface of parts of a square inch of Fig. 1. 
showing distinctly the cells ; and also a small portion of a vein 
laid open, exposing the perforations met with near the sinus 
in the concave part of the spleen ; magnified 8 diameters. 
Fig. 3. A transverse slice of the spleen of a boy 15 years of 
age. This portion had been kept in distilled water, in an open 
dish, for three days, when the mucus, which with the globules 
forms the lining of the cells of the spleen, was so much swoln, 
that not only all the cells were filled with it, but the mucus 
was raised above the surface, giving it an uneven appearance. 
The parts are of the natural size. 
Fig. 4. A surface of parts of a square inch of the above 
slice, magnified 8 diameters. 
Plate VII. 
Two sections of the spleen in different stages of maceration. 
Fig. 1. Atransverse section of the same spleen, as represented 
in PI. VI. fig. 1. After remaining 12 days in distilled water in 
an open dish the mucus is nearly dissolved, and the black spots 
