EFFECTS OF MUSCULAR EXERCISE AND THE HEAT OF 
THE SUN ON THE BLOOD AND BODY TEMPERATURE 
OF NORMAL PIGS 1 
By C. C. Palmer, 2 
Assistant Veterinarian , Veterinary-Research Laboratories, 
Minnesota Agricultural Experiment Station 
INTRODUCTION 
This work was carried out, in part, along with our studies of the blood 
of normal resting pigs. The work first suggested itself on June 25, 1915. 
We had just started our work on normal adult pig's blood, and had 
confined in a small outside pen several pigs. These pigs had been quiet, 
but it was noticed that a certain red sow was forced to lie directly in the 
sun. This animal was breathing rapidly, but was thought to be normal. 
On taking her temperature it was found to be 106 0 F., and the blood 
clotted at 15 seconds (about 60 seconds being normal). By permitting 
the animal to lie in the shade the body temperature soon returned to 
normal, as did the clotting time of the blood. A differential count of 
the leucocytes at this time showed an unusually high percentage of poly¬ 
morphs, and an. unusually low percentage of lymphocytes. Although 
we were familiar with the fact that muscular exercise causes these changes 
in the blood of man, we were surprised to learn that heat could cause 
similar changes in the blood of the pig. It was therefore decided to 
continue these studies of the pig. 
Some time after this experience several papers appeared in the liter¬ 
ature dealing with the effects of muscular exercise upon the blood of 
man; and, in carefully going over the literature, it was observed that the 
cause of the various changes in the blood of man resulting from muscular 
exercise was unsettled. , It is therefore hoped that the results of this 
work on the pig may throw a little light on these phenomena. 
METHODS OF STUDY 
The animals used in this work were normal hogs weighing about 100 
pounds. They had previously been in a resting state for a couple of 
days. They were taken from their pens, placed in a special hog crate, 
and the various determinations made. The results of these examina¬ 
tions were added to our data concerning the examination of normal 
1 Published, with the approval of the Director, as Paper No. 60 of the Journal Series of the Minnesota 
Agricultural Experiment Station. 
2 1 wish to take this opportunity to express my great appreciation of the valuable assistance rendered 
by my associate, Mr. Arthur L- Anderson, in carrying out this work. 
Journal of Agricultural Research, 
Washington, D. C. 
hw 
(167) 
Vol. IX, No. 6 
May 7, 1917 
Key No. Minn. 14 
