1. Radio-opaque material injected into the spleen of dogs and man leaves the organ quickly and in large amounts, thereby providing indirect evidence of an open circulation through the pulp.
2. The injected material does not diffuse through the pulp of the spleen but remains localized to the segments that have been injected. It is then drained by one or more veins. This is confirmatory evidence that the spleen consists of segments that are anatomically and physiologically separate. The behavior of contrast medium in the spleen of dog and man has been exactly similar. There is enough anatomical and experimental proof that the spleen of the dog has a segmental nature and the suggestion is made that this is also true of the human spleen.
3. A small quantity of contrast medium, retained apparently in the connective tissue framework of the spleen, disappears within 24 hours of injection.