THE THERMOMETER AS A COMPANION IN DAILY LIFE. 375 
independent of the pnlse-rate, therefore the quicker the pulse 
the greater the amount of work which the heart has to perform. 
This throws some light on the high temperature in pyrexia, 
consumption, and other diseases in which the heart’s action is 
conspicuously rapid ; and explains how it is that the pulse and the 
temperature so frequently tell the same tale, rising and falling 
simultaneously. 
In the animal kingdom there are two different ways in 
which the internal body-heat is distributed. In the so-called 
cold-blooded animals — including all the invertebrata, the fishes, 
amphibia, and reptiles — the temperature of the deep parts is but 
slightly higher than that of the surface, and there is no 
arrangement for maintaining a uniform internal heat. In 
birds and mammalia, the warm-blooded animals, the internal 
temperature is very constant, and much higher than that of 
the cold-blooded animals of this country. 
As the result of a large series of observations, the average 
human temperature is known to be 98°*6, and it is the same in 
the negro that it is in the Greenlander; the same in the 
Englishman, whether he is here or in Borneo. Different hot- 
blooded animals, nevertheless, have differences in their tempera- 
ture. Dr. John Davy’s observations show that in the sheep and 
goat the average is nearly 104°, in a squirrel and a rat it was 
102°, and in a hog 105°. Birds possess a temperature higher 
than that of any mammalia, it frequently reaching from 109° 
to 110°. In them the activity of the circulating and respiratory 
processes is very great. 
The human frame being thus evidently, as far as we are at 
present concerned, nothing more than a mass of matter, with a 
constantly developing internal source of heat, the next point 
that has to be considered is the mechanism by which the 
wonderful uniformity that is found to exist in the living body is 
maintained, especially when it is remembered that the varia- 
tions in the heat of the external air and coverings are so 
considerable. 
On myself, as the result of nearly five hundred observations, 
the limits of my temperature have been 97°*5 and 100°*3, a 
range of scarcely 3°, some of the results having been obtained 
in the hottest rooms of the Turkish-bath, and others whilst 
in an atmosphere of 45°. The arrangement by which so 
great a uniformity in the temperature can be obtained must be 
an exquisite one, as anybody who has attempted to hatch birds’ 
eggs in an artificial incubator, or who has at any time found it 
necessary to keep a calorimeter at a constant temperature for a 
considerable time, will fully appreciate. 
The surface of the body being constant in extent, this uni- 
formity cannot be the result of changes in that. It must, 
