May 7 ,1917 
179 
Effects of Exercise and Sun on Normal Pigs 
leucocytes after muscular exercise 
An increase in the number of leucocytes occurs in the pig. This 
increase was slight, compared to the increase found in man. 
Schneider and Havens (7) found that the normal proportion of leuco¬ 
cytes usually returned about 30 to 45 minutes after the exercise period. 
It is quite possible that in the pig a similar phenomena occurred and that 
the normal proportions had nearly returned by the time we made our 
after-exercise counts. This fact needs further investigation. 
To account for the leucocytosis, Hawk (5) concludes that it is due to 
an accumulation of leucocytes in the peripheral circulation. Zuntz and 
Schumberg (5, 7) believe that, since the white corpuscles increase so 
much .more than the red, a different explanation must obtain for their 
increase. They hold that the passing of wandering cells from the tissues 
into the general circulation is an adequate explanation. Schneider and 
Havens conclude that concentration of blood in the peripheral capillaries 
is the chief cause of the increase in the number of leucocytes. They also 
state that the contraction of the voluntary muscles accelerates the 'flow 
of lymph, throwing lymph rich in leucocytes into the blood. 
Our results in the pig show that the influences which caused an increase 
in the number of red corpuscles in the blood of man can not be used to 
explain the increase in the number of leucocytes. It would seem that 
the explanation proposed by other workers—namely, that leucocytosis 
results from the passage of leucocytes from the tissues and lymphatic 
system into the general circulation as a result of muscular contraction— 
is quite satisfactory. 
ADRENALIN THEORY 
Schneider and Havens (7) think that adrenalin is primarily responsible 
for the changes in the number of blood corpuscles in the peripheral cir¬ 
culation. They state that during muscular inaction a large mass of the 
blood is directed to the splanchnic area, where it probably stagnates 
and gives up plasm as lymph. There is also throughout the- remainder 
of the body, especially in the limbs, an accumulation of lymph. With the 
onset of muscular activity the carbon-dioxid content of the blood rises, 
this carbon dioxid stimulates the central nervous centers which regulate 
the secretion of the suprarenal glands, hence, the output of adrenalin is 
increased. The adrenalin causes a constriction of the blood vessels of 
the splanchnic area; this forces the stagnant red corpuscles into the 
general circulation, thus giving the rise in specific gravity, hemoglobin, 
erythrocyte, and leucocyte content of the peripheral blood. The increase 
in red corpuscles and hemoglobin makes it possible to supply more readily 
the greater demand for oxygen made by the active muscles. Shortly, 
after the close of the exercise the carbon-dioxid content of the blood falls 
below normal. As a result the discharge of adrenalin becomes subnormal 
and the blood once more accumulates in the splanchnic area, so that 
there is a gradual return to the normal composition and even a temporary 
subnormal content in red corpuscles. 
