Body size and metabolic rate: exponent and coefficient of the allometric equation. The role of units.

Limitations in the biological interpretation of the allometric equation describing the relationship between metabolism (oxygen consumption etc.) and body mass are pointed out. It is concluded that the fact that the relationship between different powers of body mass (W) is uniquely determined by the chosen unit of W, should suffice to put to rest the controversy about the "true" or "correct" mass exponent.