Abstract
Recently Kleiber has studied the relation in liver slices of oxygen consumption to body weight in rats, rabbits, and sheep. 1 It was shown that the Q02 was inversely proportional to a fractional power of the body weight, so that plotted on a log log grid the data gave a straight line represented by the formula
where Q02 is in mm3/mg dry tissue/hour and W is the body weight in kilos.
It was concluded that “the factors which determine the metabolic level in vivo seem still to be present in the surviving tissues cut out of the organism.”
Subsequent determinations of tissue respiration and observations on the relation of total metabolism to body size justify an additional note on this subject.
A recalculation of values from the original individual records of Kleiber gives a coefficient of correlation between log Q02 and log body weight of -0.783 and a coefficient of regression of -0.228 with a standard error of ±0.017. The formula thus becomes.
Field has since obtained data on respiration in kidney and brain slices for the rat and rabbit. Although covering only two species, the regression obtained is very similar, the average being -0.199. A value as low as this might be expected to occur by random sampling in data similar to Kleiber's about once in 10 times so that the difference can hardly be considered as significant. It is thus apparent that other tissues behave in a manner very similar to liver slices. This strengthens the view previously expressed by Kleiber.
On the other hand it is interesting to compare the exponent with that required by the surface area “law”, 0.333.
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