DISCUSSION ON TUMOR RESPIRATION 241 



Cramer and others later. The fermentation excess, U, is in fact not 

 positive but zero or shghtly negative, and the Meyerhof oxidation 

 quotient is nearer 3 than 6. 



In regard to the low or intermediate respiratory quotient of the 

 azo dye tumors of Table 1, I might comment, in view of the frank 

 discussion and expression of personal opinion desired here, that in the 

 recent discussions in Nature on the metabolism of tumors by Dick- 

 ens (7), Boyland (2), Berenblum, Chain, and Heatley (lb), and 

 Dickens and Weil-Malherbe (8b), I agree in general with the com- 

 ments of Dickens and disagree with the other commentators where 

 they take exception, for in my judgment they fail to introduce the 

 proper quantitative perspective. However, I do not feel that Dickens 

 has been correct, during the past decade, in his view that "cancer 

 tissue has a respiratory quotient indicating that the oxidation of 

 carbohydrate is abnormal" (7, p. 512). I prefer to regard the low 

 or intermediate respiratory quotient exhibited by the majority 

 of malignant tumors as being unchanged from the similar low or 

 intermediate respiratory quotient values of the great majority of 

 normal adult tissues, those, in fact, cited by him over a decade ago. 

 So why refer to them as "abnormal"? Why not consider them as 

 simply unaltered? It is the glycolytic capacity, not the respiratory 

 quotient, of tumors which by and large has changed or is "abnormal" 

 or different from normal adult tissue; it is in most growing normal 

 tissues that the respiratory quotient has tended to rise to or attain 

 unity, and the oxidation of carbohydrate to become relatively more 

 pronounced, and also the capacity for glycolysis (mainly anaerobic). 

 General confusion on these matters has led some, including Dr. 

 Elliott, in his intentionally pessimistic comments this morning, to 

 suggest, with reference to the very recent paper of Dickens and 

 Weil-Malherbe (8c) that the high glycolysis and low respiratory 

 quotient found by them for jejunum mucosa put the metabolism of 

 this tissue into the class of malignant tumor metabolism; but the 

 very high absolute Q value for respiration (about equal to the high 

 anaerobic glycolysis Q value) and the absence of a Pasteur effect 

 make this designation, in my opinion, quite impossible. Likewise, if 

 not one or two but a sufficient number of metabolic criteria (absolute 

 and relative) are considered, it is impossible to agree with the recent 

 tendency (la, and possibly 7) to regard cartilage (data, 6, 8a) and 

 synovial membrane (data, 6b) as, like the alleged skin epithehum (1), 

 providing rather good examples of normal tissues with "mahgnant 

 tumor metabolism," even after appropriate correction for inert ma- 



