522 
PHYSIOLOGY: P.D.LAMSON 
the number of red cells;^ where these changes take place; whether the 
increase in number is relative or absolute; and finally if there is a mech- 
anism controlling the red corpuscle content of the blood, and if so what 
is its function. 
It has been found that asphyxia in any form causes the number 
of red cells to increase. Reduced atmospheric pressure, reduced partial 
tension of oxygen, obstruction of the air passages, reduced oxygen ca- 
pacity of the blood, as in carbon monoxide poisoning, or increased 
oxygen consumption as in exercise, will cause an increase in the num- 
ber of red cells. Furthermore, obstruction to the circulation in the 
lungs, and consequent interference with the oxygenation of the blood, 
as in congenital heart conditions, will cause polycythaemia. I have 
been able to produce this form of polycythaemia experimentally by the 
injection of either corpuscles hardened with formaldehyde, or an inert 
powder as lycopodium, or oil, thus inducing embolism of the lungs and 
obtaining as great an increase in the number of red corpuscles as 
3,000,000 in fifteen minutes. 
Besides, it is known that various substances occuring physiologically 
in the body as epinephrin, pituitrin, carbon dioxide, and substances 
entirely foreign to the body as nicotine, radium chloride, etc., may pro- 
duce very marked changes in the red count. 
And finally I have been able to show that the number of red cells 
is under nervous control. In cats frightened by a dog for a minute or 
so, the red count rose one or two milKons in five minutes or less, and 
from excitement alone reached the extreme value of 16,776,000 in one 
instance and 14,464,000 and 14,920,000 in two other cases. 
There has been a great deal of work done concerning the magnitude 
of the changes in number of red cells and the haemoglobin content of 
the blood at high altitudes, and in exercise, but up to this time there 
has been no experimental evidence as to the seat of the changes which 
cause this increase. On this account the following experiments were 
systematically undertaken to find out if possible where the changes 
take place which cause an increase in the number of red cells. 
For this purpose epinephrin was chosen as a means of producing 
polycythaemia, as it can be obtained in a pure state, accurately gradu- 
ated in amount, and appHed as a stimulus with certainty when intra- 
venously injected. Furthermore it occurs normally in the body, and 
ether does not interfere with its action. When injected in doses of 
0.9 mg. per kilo, intravenously, it produces with great regularity an 
increase of one or two milHons in the red count in fifteen or twenty 
minutes. 
