September 2, 1921] 



SCIENCE 



199 



production of heat. It is this causal relation- 

 ship to which Benedict and Talbot in their 

 latest publication make objection. They say, 



As the result of the critique of the body surface 

 law presented by Harris and Benedict, we believe 

 that the accurate measurements of body surface 

 made possible by DuBois may legitimately be used 

 in a manner heretofore never practicable in metab- 

 olism experiments, provided that they are con- 

 sidered as physical measurements and with no 

 erroneous conception as to the existence of a 

 causal relationship between surface area and heat 

 elimination.^ 



l^evertheless they compute many of their 

 measurements by the Lissauer formula and 

 find that many others as given by the DuBois 

 linear meastirements agree with the Lissauer 

 formula provided a " constant " varying from 

 10.0 for infants up to 6 kgm. to 11.5 for 

 youths between 25 and 40 kgm. is used. How 

 the use of a physical measurement instead of 

 a formula which agrees with the physical meas- 

 urement improves matters it is difficult to see. 

 The elaborate biometric analysis of Harris 

 and Benedict has proved nothing more regard- 

 ing the causal relationship than is proved by 

 the simple mathematical analysis shown in 

 Table I. Whatever the physical measurement 

 of surface, if it can be expressed even approxi- 

 mately by a formula such as Lissauer's, it 

 will follow that the ratio of body weights for 

 certain ranges will be the same as the ratio 

 of body surfaces provided the weights are not 

 far apart, and for subjects of a continuous 

 series in which weights differ by small incre- 

 ments it will follow that surface will be only 

 a little, if any, better as a measure of metab- 

 olism than weight. 



The question of causal relationship stands 

 just where it always has stood. If the posses- 

 sion of a large surface in proportion to weight, 

 as in a mouse, is accompanied by a vastly 

 higher heat production per unit of weight as 

 compared with a horse, but the heat produc- 

 tion is found to be proportional to the surfaces 

 of two such animals with approximately the 

 same body temperature, it seems to follow that 

 surface loss of heat is at least a more probable 



Benedict and Talbot, loc. oit., p. 159. 



cause of heat production than body mass. The 

 same is true as between a baby and a man. 

 How else are such facts to be explained? 



A word as to the teleological aspect of the 

 case. Since heat production of animals seems 

 to be proportional to surface area, it would 

 seem to follow that heat is produced in order 

 to replace that which is lost, or to maintain 

 body temperature. This view some say, de- 

 notes an all too naive conception of nature. 

 Blood does not coagulate in order to prevent 

 hemorrhage, but because certain chemical 

 agents are present and certain properties. The 

 fact that it does stop hemorrhage is quite in- 

 cidental. It may have selective value, so that 

 a species whose blood did not clot would have 

 the worst of it in the struggle for existence, 

 but it will never do to say that this chemical- 

 physiological function originated for the pur- 

 pose of preventing hemorrhage; for that 

 would imply a mind at work in anticipation of 

 the result. So also with heat production. 

 These critics, of whom Kassowitz has been 

 chief, prefer to account for heat production 

 in a perfectly causal manner. 



Small animals maintain a higher rate of oxi- 

 dation, it is true, than large ones, but this is not 

 because they lose heat more rapidly in conse- 

 quence of greater (relative) surface, but because 

 their alternating movements (later phases caused 

 refiexly by earlier phases) follow one another more 

 rapidly on account of shorter nerve paths.' 



Eassowitz indeed finds that the higher rate 

 of oxidation in small, warm-blooded animals 

 has even for them " dysteleological conse- 

 quences; for because of the more extensive 

 muscular contractions more food and reserve 

 substances are placed in requisition and by 

 this means the deposit of reserve fat in the 

 whole body, and especially in the subcutane- 

 ous tissues, is made more difficult, so that 

 the protection against cooling — which a thick 

 layer of fat prevents — fails in part amongst 

 the very animals which need it most." ^ Even 



7 Kassowitz, M., ' ' AUgemeine Biologic, ' ' 1904, 

 Chap. XXV., par. 40. 



6 Kassowitz, M., "Der grossere Stoffverbrauch 

 der Kinder," ZeHschr. f. Kinderheilk., 1913, VI., 



247. 



