Sept. 8, i 9 a 5 Determination of Surface Area of Cattle and Swine 421 
to the animal body as forcefully as to the human body. The heat out¬ 
put does not depend on Newton’s law of cooling and it is not proportional 
to the body surface under all circumstances. In the opinion of the 
writers, however, this method of computing energy transformations has 
great advantages over any hitherto proposed. 
Whether Benedict's objection is valid or not, in practice the animal 
husbandryman has some difficulty in comparing the metabolism of his 
experimental animals per unit of surface area. The proper constants have 
been determined in only a few instances, so it has been impossible to 
calculate the surface areas of the ordinary farm animals with any degree 
of accuracy. That difficulty was avoided, however, by making the 
calculations on the basis of a uniform weight, as was the practice of 
Armsby (1, p. 260). According to the Meeh formula, this means that 
the surfaces of animals are proportional to the two-thirds powers of 
their weights. If the formula is correct, that method would be satis¬ 
factory. As a matter of fact, it soon became evident that the formula 
may give very erroneous results. Trowbridge, Moulton, and Haigh (14) 
published a number of measurements of the surface area of cattle, and 
calculated the constant for the Meeh formula, expressed as follows: 
Of the cattle investigated, the variations were extreme, and the constants 
varied from 7.319 to 10.474. The constant was greatest for the thinner 
and younger animals and least for those older and fatter. 
Some time later Moulton (9) developed two formulae, differing some¬ 
what from that of Meeh. The formula for fat cattle is: 
A =0.158 W* 
and for other animals: 
A =0.1186 W* 
A is the surface area in square meters, W is the empty weight in kilo¬ 
grams. 
The work of Trowbridge, Moulton, and Haigh ( 14 ) and of Moulton (9) 
makes it clear that a simple formula of the Meeh type is not applicable to 
cattle. At about the same time that their work was published, E. F. and 
D. Du Bois (4) and collaborators had reinvestigated the formula as applied 
to man, and showed that it leads to serious errors. They (5) finally 
devised their “height-weight” formula which seems to be quite exact. 
The formula is: 
A^W 0 - 425 XH 0 - 725 XC 
A is the surface area in square centimeters, H the height in centimeters, 
W the weight in kilograms, and C the constant 71.84. The error was 
estimated to be ±5 per cent as a maximum. The error with the Meeh 
formula as applied to their subjects {13) ranged from 4.9 to 38.0 per 
cent. 
It is evident from the work of the Du Boises on man and of Moulton 
on cattle that the surface area can not be accurately calculated as a 
power function of the weight. Accordingly, we have attempted to devise 
a formula that would permit a more accurate calculation of the surface 
area of cattle and swine. The “height-weight” formula of Du Bois was 
taken as a guide. 
