PHYSIOLOGY: P. D. LAMSON 
365 
Imbedded in this mineral and like it derived from some mineral that 
has disappeared, are spherulites of an undetermined mineral with rather 
strong birefringence, positive elongation, and a mean index of refraction 
of about 1.50. 
1 Emmons and Larsen, The hot springs and the mineral deposits of Wagon Wheel Gap, 
Colorado, Economic Geology, 8, 235 (1913). 
2 Published with permission of the Director of the United States Geological Survey. 
' Unpublished manuscript by Esper S. Larsen. 
^ Dana, A System of Mineralogy, sixth edition, p. 181, 1892. 
THE PROCESSES TAKING PLACE IN THE BODY BY WHICH THE 
NUMBER OF ERYTHROCYTES PER UNIT VOLUME 
OF BLOOD IS INCREASED IN ACUTE EXPERI- 
MENTAL POLYCYTHAEMIA 
By Paul D. Lamson 
PHARMACOLOGICAL LABORATORY, JOHNS HOPKINS UNIVERSITY 
Received by the Academy, June 9, 1916 
In a previous communication to the Proceedings^ I reviewed the 
work of the past on polycythaemia, and reported a series of experiments 
carried out in the hope of determining if possible the process by which 
the number of erythrocytes per unit volume of blood is increased in 
acute experimental polycythaemia. Since then further experiments 
have been undertaken, some of which have already been reported.^ 
The results of these experiments, and others about to be published, are 
collected here in a brief summary of this work up to the present time. 
This complicated problem may be divided into four maiii parts: 
(1) The causes capable of producing an increase in number of erythro- 
cytes per unit volume of blood. 
(2) Localization of these processes. 
(3) The manner in which the number of erythrocytes is increased. 
(4) The mechanism by which the red corpuscle content of the blood 
is controlled. 
As previously pointed out, the causes of polycythaemia are very 
numerous, and have received a great deal of attention, but little work 
has been done concerning the locaHzation and manner in which this 
increase in number of erythrocytes is brought about. 
From experiments previously reported, the present author con- 
cluded that the liver is the organ which is responsible for the changes in 
number of erythrocytes produced by the intravenous injection of 
epinephrin.^^ This conclusion has been confirmed by the following 
experiments here summarized. 
