96 



Brixton Chance 



sources are given in Table 



I. Since the measurement of 

 respiratory control ratios in excess of 20 : 1 taxes the accuracy 

 of the polarographic method used under these experimental 

 conditions, we have, in this table, placed those ratios exceed- 

 ing this value in parentheses. It is clear that respiratory 



* Experiments in collaboration with Dr. F. Jobsis. 

 t Experiments in collaboration with Dr. J. Ramirez. 



control ratios of over 10 : 1 can be obtained from most 

 tissues which have been carefully studied. Mitochondria 

 prepared from cells in which the membrane is so resistant to 

 rupture that damage to the mitochondrial membrane ensues 

 may show respiratory control ratios of less than 10 : 1. 



Most of the respiratory control ratios given in Table I 

 were measured in the presence of a DPN-linked substrate 



