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used the term lobule in a vague sense (p. 548), corresponding more with 
my histological unit. This division is also accepted by Hoyer.’ Kyber’s 
lobes correspond with the-arterial branches which enter the spleen, and 
form about ten unequal subdivisions of the spleen substance. The lob- 
ules I have described are about a millimeter in diameter and can easily 
be seen on the surface of the organ, or in sections. They are not to be 
confounded with Kyber’s lobules. 
That the terminal artery and the ampulla are very porous is shown 
easily by injecting the artery with any fluid, such as carmine gelatin, 
which in all cases passes over into the pulp at once, filling all of its 
spaces and the veins evenly. Such specimens naturally lead one to con- 
clude that the circulation through the spleen is open, and were it not 
for other facts all anatomists would be willing to accept this conclusion. 
And when the spleen is evenly injected with carmine gelatin it is im- 
possible to find the end of an artery with any degree of certainty, and 
it is very exceptional to find one reaching to a vein. 
If a spleen, made oedematous by injecting gelatin into either the vein 
or the artery, or by filling the pulp with blood by ligating the vein for 
half an hour, is injected through the artery with some fine granular 
mass like Prussian blue, it is found that at the end of each arterial 
capillary there are a number of ampullae which communicate with the 
pulp-spaces, with one another and with the veins. It seems as if the 
ampullae are only large holes within the spongy pulp. A picture show- 
ing this arrangement is given by me in my article in the Zeitschrift 
fiir Morphologie und Anthropologie, Vol. II, Fig. 12. It must be remem- 
bered, however, that in all such specimens a considerable quantity of 
the Prussian blue has passed over into the smaller pulp-spaces. If the 
injection is continued until the veins are well filled all the pulp-spaces 
are also filled with the blue. Free communications between the ampullae 
and veins have been seen from time to time by numerous investigators 
from W. Miiller to Helly, but no one has ever been able to find them 
- In great number nor free from extravasations. In fact, a recent inves- 
tigator, who no doubt is strongly inclined towards a closed circulation, 
states expressly that he could not find a single communication between 
the artery and the vein.” 
The first third of the ampulla is lined with spindle-shaped cells 
which are directly continuous with the endothelial cells of the artery. 
The second third branches and often communicates with neighboring 
* Hoyer, Morph. Arbeiten, Bd. [II, 267. 
10 Von Schumacher, Arch. f. mik. Anat., LV, 1899. 
