less complete
exclusion of the spleen from the formation of the blood; since Ehrlich
has distinctly asserted that the probable place of formation of the
eosinophil cells is the bone-marrow."

From what has been brought forward no doubt can now remain that the
question has been decided quite in Ehrlich's favour.

But what then are the physiological functions of the spleen, since that
organ is unnecessary for the persistence of life? Doubtless its chief
duty is the taking up of the greater part of the decaying fragments of
red and white blood corpuscles in the blood-stream, so that this
valuable material is not quite lost for the organism. Thus Ponfick has
found that after destruction of the red corpuscles the spleen takes up a
portion of their "shadows," and for this reason calls the splenic tumour
a spodogenous splenic tumour ([Greek: spodos], ruins). Ehrlich has made
a corresponding observation for the products of dissolution of the white
blood corpuscles, and has proved that the splenic tumour which occurs in
many infectious diseases and in phosphorus poisoning is to a large
extent caused by the parenchyma of the spleen taking up the remains of
the neutrophil protoplasm.

The question of the relation of the spleen to the =fresh formation of red
blood corpuscles= is a problem of comparative anatomy. Observations on
this point made on one kind of animal can certainly not claim validity
for other kinds. In lower vertebrates, as in fishes, frogs, tortoises,
and also in birds, the blood-forming activity of the spleen is
pronounced and of great importance. In mammalia on the other hand, in
some cases this function cannot be demonstrated, and in others only to a
very small degree. In the spleen of normal mice nucleated red blood
corpuscles are seen in relatively large numbers; in the rabbit they are
less numerous and often only to be found with difficulty. In the dog
they only make their appearance after anaemia from loss of blood,
normally they are absent. =In the human spleen nucleated red blood
corpuscles are not to be found normally or in cases of severe anaemia,
but exclusively in leukaemic diseases.= U. Gabbi in his recently published
work on the haemolytic function of the spleen, also emphasises the
difference between the various animal species. In guinea-pigs he found
that the spleen acts largely as a scavenger of the red blood corpuscles;
in rabbits very slightly. Consequently after removal of the spleen in
guine