186 V E. HENDERSON. 



papillae. Like Lindemann I have also noted that one of the first 

 effects of pressure was flattening of the papillae and hence probably 

 closure of the tubules opening there. 



This fresh evidence, like the work of Cushny, Loewi, Sollmann, 

 Rtidel, Hiiber and others, furnishes a new support to the theory of the 

 recurrence of absorption. The close relationship which in the earlier 

 part of the paper was shown to exist between the blood-pressure and the 

 blood-constitution on the one hand and the ureter-pressure on the other 

 and the fallacies, incorrect pressure measurements, shown to exist in the 

 work which was supposed to disprove this relationship point more clearly 

 to the correctness of the filtration-reabsorption hypothesis than to that 

 of specific secretion. 



It gives me much pleasure to be able to thank Prof. Starling for 

 permitting me to carry out the above experiments in his laboratory and 

 for much kind advice and criticism received from him. 



CONCLUSIONS. 



1. The ureter-pressure depends, in the first instance, on and varies 

 with the blood-pressure and is not a secretion-pressure properly so- 

 called. 



2. The minimum difference between ureter-pressure and blood- 

 pressure will vary firstly with the rate of urinary production, and secondly 

 with the proteid constitution of the plasma, and that hence the explana- 

 tion given by Starling firstly of the dimension of the observed minimal 

 difference between blood and ureter-pressures, and secondly of the 

 absence of urinary flow with low blood-pressures and a normally 

 constituted plasma, is probably correct. 



3. Reabsorption of water and of slightly diffusible substances may 

 take place from the tubules. 



