242 



GROWTH 



PRINCIPLES AND THEORY 



TABLE 16 



INTRASPECIFIC AND INTERSPECIFIC ALLOMETRY (CONSTANTS a) 

 IN ORGANS OF MAMMALS 



After Bertalanffy and Pirozynski, 1952 



Rat Cat 



B. and P. Brody 



Dog Monkey Cattle Horse 



Adult 



mammals 



interspecific 



Brain 



Heart 



0.20 0.1 



0.80 



90.82 



Lungs 0.73 0.75 



Liver i. Cycle: i. Cycle: 



1.26 1. 14 



2. Cycle: 2. Cycle: 



0.67 0.68 



Kidneys 0.80 0.82 c5 0.65 



9 0.61 



0.25 0.62 0.30 



1. 00 0.69 0.93 



0.86 



0-93 



0.82 0.92 



0.24 



0.71 



0.70 



0.70 



0.58 

 0.61 



0.66 



0.66 

 0.69 

 0.58 

 0.54 



0.83 

 0.82 

 0.85 

 0.84 

 0.98 



0.98 

 0-99 



0.87 

 0.88 

 0.92 



0.85 

 0.87 

 0.76 



Bibliography cf. original. 



For example, basal metabolic rate in the series of adult mammals "from the mouse to 

 the elephant" is proportional to the 3/4-power of body weight (Brody, 1945 ; Kleiber, 1947). 

 Hence organs such as the kidneys, liver and heart will increase corresponding to the demands 

 of metabolism including a safety factor, i.e. with an allometry exponent above 0.75. In 

 the lungs gas exchange takes place. Their enlargement must be approximately weight- 

 proportional if respiratory surfaces (which, neglecting structural changes, would increase 

 as a 2/3-power of weight) are to increase corresponding to the demands of oxygen con- 

 sumption. Actually the lungs do have an allometry constant a ~ i. With respect to the 

 brain, E. Dubois' concept may be remembered that information from the environment is 

 chiefly received on the body surface; or (Quiring, 1941) that the brain regulates the heat 

 production of the organism, and heat output takes place on the surface. In both cases an 

 approximate surface-proportionality of brain size is to be expected and also is found in 

 interspecific comparison. Similar functional considerations can be applied to the wings 

 of birds (Meunier, 1951) which show positive ontogenetic allometry and negative inter- 

 specific allometry. 



On the other hand, different species are born in different stages of maturation. 

 Hence, in order eventually to establish the required balance of organs in the 



