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PHYSIOLOGY: P. D. LAMSON 
(1) Epinephrin when injected into a dog or cat intravenously in doses of 
0.9 mg. per kilo causes an increase in number of erythrocytes of 1.5 to 2.0 
millions per cubic millimeter of blood in from five to ten minutes, lasting about 
one half hour and then gradually returning to normal. 
(2) Removal of the stomach, intestine, mesentery, omentum, pancreas, and 
spleen, either singly or all together has no appreciable effect on this reaction 
to epinephrin. 
(3) A head-thorax animal does not respond to epinephrin. 
(4) The addition to the head-thorax animal of the liver, supplied by 
arterial blood only, gives an animal which responds to epinephrin. 
(5) Removal of the liver from the circulation by ligation of the hepatic 
artery and shunting the portal bood around the liver by means of an Eck 
fistula, gives an animal in all respects normal except for the absence of the 
liver. Epinephrin in such an animal causes no increase in number of ery- 
throcytes per unit volume of blood. 
(6) In an animal in which all arterial blood supply to the liver is shut 
off by ligation of the hepatic artery (the portal circulation being left intact), 
epinephrin causes no increase in number of erythrocytes. But if one half 
hour or later, after the injection of epinephrin, arterial blood is again allowed 
to reach the liver by removal of this ligature, the number of erythrocytes is 
immediately increased as if a fresh dose of epinephrin had been injected into 
the animal. 
(7) In an animal in which the arterial blood supply to the liver is shut off 
by ligation of the hepatic artery the injection of epinephrin into the portal 
vein causes an immediate increase in number of erythrocytes. 
From these experiments it is evident that it is necessary for the 
liver to be present in the circulation for polycythaemia to take place. 
If epinephrin does not reach the liver as is the case when the hepatic 
artery is Hgated (the epinephrin being probably adsorbed to a great 
extent in its passage through the other portal organs) no polycythaemia 
takes place. But if in this condition, epinephrin is allowed to reach 
the Hver by injecting it into the portal vein, polycythaemia takes place 
at once. 
As regards the manner in which the number of erythrocytes per unit 
volume of blood is increased following the injection of epinephrin we 
know that it must take place in one or more of the following ways. 
(1) A decrease in plasma volume. 
(2) An absolute increase in number of erythrocytes by (a) a forma- 
tion of new erythrocytes, (b) a division of erythrocytes (a theoretical 
consideration), (c) bringing erythrocytes into the circulating blood 
from a reservoir or reservoirs in the body. 
The following facts have been experimentally demonstrated. 
