A New Conception of the Glomerular Function. 575 



urine at a very fast rate. Such an absorbing surface would be influenced, as 

 indeed is usually assumed by the supporters of Ludwig's theory, by a rise in 

 pressure of the fluid at the surface. It then becomes very difficult to explain 

 how the ureter pressure could ever be driven so high as is usually observed, 

 especially when we remember that the rise in pressure can be effected with 

 great rapidity. 



Yet another result obtained in these experiments upon maximum ureter- 

 pressure is very significant. I have found that the maximum ureter pressure 

 is practically the same whether the kidney be made to secrete a moderate 

 amount of urine or a very large quantity. If reabsorption be a very active 

 process, then the maximum ureter pressure in the latter case ought to be 

 distinctly higher than in the former. As a matter of fact, it is not. 



Taking everything into account, therefore, I have very grave doubts as to 

 the occurrence of reabsorption in the tubules, and I am sure, if it does take 

 place, that it is insignificant in comparison to that demanded by Ludwig's 

 theory. 



The Function of the Glomerulus. 

 Arriving then at the conclusion that the filtration theory was incorrect, I 

 came back once more to the old problem : How are we to explain the very 

 peculiar and characteristic structure shown by the glomerulus ? I finally hit 

 upon the idea that it was simply a means of utilising the blood-pressure for 

 setting up a pressure head sufficiently great to drive the urine secreted at 

 the glomerular surface down the tubule. To express this idea I term the 

 glomerulus a propulsor. As is abundantly proved, the main volume of the 

 water of the urine is secreted into the capsule of the glomerulus. To drive 

 it from the capsule down the tubule requires a definite pressure-head. 

 Whence is this pressure head derived? My view is that the intraglomerular 

 blood-pressure is transmitted directly through the thin-walled glomerular 

 loops to the fluid which has been secreted into the capsule, and thus a 

 pressure is communicated to the fluid sufficient to force it down the tubule. 

 To test this view, let us imagine that a certain amount of fluid has accumu- 

 lated within Bowman's capsule. The problem then becomes : How is that 

 fluid discharged down the tubule ? If we know the number, length and 

 lumina of the tubules, and the total amount of fluid leaving the kidney within 

 a given time, it becomes easy to calculate the pressure-head which must 

 have existed within each capsule in order to drive the fluid out of the kidney. 

 It is simply an application of Poisseuille's law. I therefore performed two 

 experiments upon the following lines. An active diuresis was established 

 in an anaesthetised dog, and the rate at which urine was being discharged 

 from one of the kidneys was determined. The pedicle of the kidney was 



