DR. PAVY AND DIABETES 19 



for analysis, an increase which may well fall within the limits 

 of experimental error. Whilst, therefore, an experimental proof 

 of Bernard's theory cannot be obtained on these lines, a dis- 

 proof is equally impossible. 



The arguments which Pavy based upon his view of the renal 

 function, though they seemed to him to appeal to common sense 

 and to be conclusive, were, on the other hand, essentially 

 a priori. That no increase of sugar takes place normally in 

 the urine as the result of a carbohydrate meal merely demon- 

 strates the perfection of the regulative activity of the liver : 

 the organ maintains the concentration of blood-sugar at a 

 value near to a mean, in spite of great fluctuations in the supply 

 from the intestine. On the glycogenic doctrine, fluctuations in 

 the demands of the tissues would, it is true, involve a fluctuating 

 output of sugar from the liver and any such fluctuations, Pavy 

 assumed, should be promptly registered by the kidney. This 

 assumption is not wholly valid, however. Increased demands 

 for sugar in individual organs may be met, in part or whole, by 

 increased velocity in the local blood flow rather than by increased 

 concentration of sugar in the blood. In many cases, again, 

 increase in the oxidation processes of the tissues in general 

 is associated with increased activity in the kidney itself {e.g. 

 in the adjustment of the body following a lowering of external 

 temperature) and this organ is one with a high-grade metabol- 

 ism, likely to utilise rather than to excrete any temporary 

 excess of sugar which passes it. Finally, though we know 

 that the kidney is extremely sensitive to increases of sugar 

 in the blood of above a certain amount, it is more than a mere 

 filter and we do not know that such small variations as might 

 be sufficient to cover the fluctuating demands of the tissues 

 would be registered in it. 1 



It is striking to find that a direct proof that sugar may 

 increase in the circulation without glycosuria, far more con- 

 vincing than such considerations as the above, was to be 

 furnished by the very last of Pavy's own work which came 

 to publication. In conjunction with Mr. Godden, 2 he injected 

 sugar into the venous circulation of rabbits — under conditions 

 which were more physiological than those of earlier experiments 

 of the same type ; and found that no less than 2 grammes of 



1 Cf. E. Frank, Zeitsch. f. Physiol. C/iem. 70, 291 (191 1). 

 * Pavy and Godden, fourn. Physiol, xliii. 199 (191 1). 



