420 
Journal of Agricultural Research 
Vol. XXV, No. io 
solids—that is, the surfaces are proportional to the two-thirds powers of 
their volumes. If the specific gravity were the same in each case, then 
the surface areas would also be proportional to the two-thirds powers of 
the weights. The formula of Meeh may be expressed as follows: S = KW*. 
S is the surface area in square centimeters, W is the weight in grams, and 
K is the constant 12.312 for adults and 11.9 for children. According to 
Meeh’s calculation the extreme variations were ± 7 per cent. 
A few years later Rubner (11) measured the surface area of a number 
of dogs and determined their heat production under comparable condi¬ 
tions. All the animals were mature, in the condition of inanition, and 
the surrounding temperature was approximately the same. The heat 
produced is given in 24-hour periods, measured at a temperature 
of 15 0 C. 
Table I .—Heat production in relation to body weight and surface area 
No. of dog. 
Average body 
weight. 
Calories liberated— 
Per kilo 
body weight. 
Per square 
meter surface 
area. 
1.. . 
11.. 
III. 
IV. . 
V. .. 
VI. . 
VII. 
Kgm. 
31. 20 
35-68 
1,036 
24. OO 
40 . 91 
1,112 
19. 80 
45-87 
1, 207 
l8. 20 
46. 20 
1,097 
9. 6l 
65. 16 
h 183 
6. 50 
66. 07 
3 - 19 
88. 07 
1, 212 
The heat production per kilo varied widely, but was quite constant per 
square meter of body surface. 
Some years later Rubner ( 12 ) conclusively demonstrated that the oxi¬ 
dation processes within the body are alone sufficient to account for the 
entire heat production. He constructed a respiration calorimeter and 
made seven experiments on dogs. These covered in all a period of 45 
days, and the average heat production determined directly from the cal¬ 
orimeter differed from that computed from the respiration apparatus by 
less than one-third of 1 per cent. 
Thus, after the lapse of more than one hundred years following the 
original pronouncement of Lavoisier (6), it was conclusively demonstrated 
that the oxidation processes alone could account for all the animal heat 
produced. It was shown clearly that the quantity of heat produced was 
not proportional to the weights of the animals, but it became reasonably 
certain that the quantity of heat does bear some direct relation to the 
surface area of the subjects investigated. Accordingly, it has become 
the practice of many investigators when comparing the energy transfor¬ 
mations of animals of different weights, to compare the heat production 
per unit of surface area. 
Before dismissing the historical phase of the subject, mention should 
be made of the fact that Benedict (2) has sharply challenged the practice 
of calculating heat production per unit of surface area, and concludes 
“that the metabolism or heat output of the human body, even at rest, 
does not depend on Newton’s law of cooling and is therefore not pro¬ 
portional to the body surface.” Benedict’s statement applies of course 
