524 
PHYSIOLOGY: P. D. LAMSON 
liver, spleen and pancreas, and part of the stomach, but we have seen 
that removal of all of these except the liver has no effect on the pro- 
duction of polycythaemia after injection of epinephrin. If then the 
coeliac axis artery is ligated, and epinephrin injected, no change in the 
number of red cells is observed, but if this ligature is removed, even 
one-half hour after the injection of epinephrin, the red count will imme- 
diately increase, as if the usual dose of epinephrin had been injected into 
a normal animal. 
A control experiment was done in which the coeliac axis artery was 
ligated, and after half an hour the ligature removed. This had no effect 
on the red count, which shows that mere interruption of the arterial 
circulation to the liver is not the only factor necessary to change the 
number of red cells. 
I have also shown that ligation of the portal vein, as in the operation 
of removing the intestine, has no effect on the production of polycythae- 
mia following the injection of epinephrin. Also in those cases in which 
the hiepatic artery was ligated, epinephrin was carried to the liver by the 
uninterrupted portal circulation, and yet no change in the number of 
red cells took place. 
Furthermore, in cases where the hepatic artery was tied, injection 
of epinephrin caused no increase in the number of red cells, although 
there was no interference with the blood supply to the kidneys, bone 
marrow', muscles, lungs or skin. These organs may then be considered 
as playing no part in the production of polycythaemia due to epi- 
nephrin injection. 
It appears then that the liver is the organ capable of increasing the 
red corpuscle content of the blood after injection of epinephrin, and 
that the arterial blood supply to the liver must be intact to allow these 
changes to take place. 
As to the changes which occur in the liver certain facts were observed 
in these experiments. There is a decrease in plasma volume, not how- 
ever sufficient to account entirely for the increase in number of red 
cells. There are cells present in the circulation during polycythaemia 
which were not there before its production, as shown by a decrease in 
the average size of the red corpuscles, and a decrease in their percent- 
age haemoglobin content. These cells show none of the usual signs of 
young cells. That is, they are not nucleated, they show no change in 
fragiHty, and they have no increased metaboHsm such as would result 
in an increased rate of reduction. 
Concerning the mechanism which normally controls the red count, a 
few points of interest were observed. 
