130 
Proceedings of the Royal Society of Edinburgh. [Sess. 
Dr Wilson, I was permitted to extract from the records of the Ithaca Station 
of the United States Weather Bureau, and it was a fortunate circumstance 
that this station should be located on the top of the Agricultural College 
Buildings, only about 150 yards distant from the hen pens. The percentage 
of humidity is not available for the afternoon, only a single daily observation 
having been made, and that at 8 a.m. 
Results and Discussion. 
From an examination of the tables and charts it will be found that the 
body temperature curve, in a general way, rises and falls with the 
temperature of the air, but the relationship is not a close one, unless when 
the external temperature is very low or very high. Considering the 
records of the whole pen for the first year only, the Buff Orpingtons and 
White Wyandottes have the lowest rectal temperature in December, the 
Barred Plymouth Rocks in January, the Brown Leghorns, White Plymouth 
Rocks, and Rhode Island Reds in February ; December, January, and 
February are therefore the months when the body temperature is lowest, as 
also that of the external air. It would be erroneous to conclude from this, 
however, that the low external temperature is the only cause of the fall 
in body temperature, since two other factors come into operation, viz. 
muscular exercise and sunlight. As mentioned previously, during the 
winter months the fowls, either from choice or compulsorily, remain indoors 
for the most part, the ground being covered with snow, and have not the 
same opportunity for exercise as in the summer months, when they prefer 
to be outside in the run scratching amongst the dry earth. In November, 
December, and January the sunshine is also at a minimum, and both these 
influences may have an effect on the body temperature. 
In all cases the highest body temperature is found in June, July, and 
August, when the weather is at its hottest, and the rise is a very distinct 
one. Here the important factor is evidently the external temperature, 
since the hens are under practically the same conditions with regard to 
exercise from March till November, and by consulting the weather table 
it will be seen that the hottest days in June, July, and August were to a 
large extent sunless days. For example, the total sunshine on May 5, and 
September 21, 1910, was 142 and 12 '2 hours respectively, as against 8‘8 on 
June 28, and 6*8 on August 23. It was observed on days when the 
thermometer stood in the neighbourhood of 90° F. that slight exertion was 
sufficient to cause in the hens distressful symptoms, such as panting with 
open mouth, and rapid respiration. 
