43 
structure of the brain and nerves, &c. 
parts ; also a branch of an artery whose anastomoses compose 
a beautiful net-work almost over the whole membrane of the 
retina. 
This representation of an arterial branch, may serve as an 
illustration of those that pervade every part of the substance 
of the human brain ; but such branches do not any where 
anastomose except in the retina. 
Plate III. 
This Plate consists of six figures. The first representing a 
portion of the spleen. The second, third, and fourth, the ves- 
sels with valves passing from the internal membranes of the 
stomach. The fifth and sixth, the blood ‘globules and salts in 
the blood of the skate. 
Fig. i. A surface of parts of a square inch of a slice of 
the spleen of a child five years old, minutely injected for the 
arteries ; magnified 8 diameters. It shows the termination of 
the arteries in the empty cells, which are also filled with the 
injection, in the same manner as the corpuscules themselves 
are originally formed. 
Fig. 2. A small slice of the coats of the cardiac portion of 
the human stomach, magnified 8 diameters, from a man 48 
years old. The blood vessels Were minutely injected soon after 
death, the arteries with red, the veins with yellow ; the cellular 
membrane, or rather the filamentous substance between the 
villous and muscular coat, is in this figure stretched out to 
more than three times its natural thickness, and it is in this 
space that the empty valvular vessels are distinctly shown. 
Fig. 3. and 4. Portions of the small valvular vessels, show- 
ing that they vary in appearance ; magnified 400 diameters. 
