122 Proceedings of the Royal Society of Edinburgh. [Sess* 
CHART I.— Pen I., Barred Plymouth Rocks, 9. 
Shows mean rectal temperature, on dates given, of twenty-three hens for one year, and of eight 
for two years ; also temperature of air in pen, barometric pressure, and egg -production on same 
dates. The figures on the right margin (degrees centigrade) refer to the lower of the two rectal 
temperature curves. This applies to all the charts. 
