1922. ] ‘** Renal Portal’? System. 131 
the filtrate most required to be retained by the body——,and 
the Tubule cum Rete theory, which is the very antithesis of the 
neo-Ludwig theory in that it assumes that all the constituents 
of the urine are secreted Ay the tubules.! The function of 
the glomerulus, according to the Tubule cum Rete preenies is 
that which i is probably to be attributed to most or all other 
forms of retia mirabilia, viz. the reduction of the arterial pressure 
(since high blood pressure in the intertubular plexus means 
excessive loss of malt and deficient elimination of nitrogen, i.e. 
the reversal of the result demanded by the body) and the 
retardation ( => flow in the intertubular plexus involving un- 
due loss of water from the body) and making continuous of 
the iieial flow, while maintaining a large volume of blood. 
e way in whi ch the glomerulus produces these effects will be 
explained below, and suggestions will also be offered in expla- 
nation of the well-known but little understood fact that the 
glomerulus, unlike most other retia mirabilia, becomes en- 
capsule 
For the sake of brevity I shall not attempt to discuss the 
relative values of these rival theories from every point of view : 
all that I shall undertake is to state certain facts, mostly de- 
rived from my own work, which I believe to be fatal to the neo- 
Ludwig theory, to reconsider some pat facts which are either 
for or against this theory, and t er certain objections 
which have been or siabauiy will net levelled again the theory 
which I believe to be the true one. 
Some Facts subversive of the see Theory oj 
Kidney Secretion 
{1) Quantity of Urine is dependent _— the Quantity of Blood or other Per- 
fusing Fluid A Volume x "Rate 0 of Flow ) traversing the Intertubular Plexus 
luid Pressure in the eruli. 
If the ae walls of the glomerulus and the capsule 
wall filter off only the non-colloid constituents of blood, then 
both blood pressure and blood flow must be important factors 
in filtration, but in perfusion experiments in which the whole 
of the circulating fluid is filterable, fluid pressure can be the 
only factor concerned. If glo merular filtration be a fac t, quanti- 
ty of urine in perfusion peg erat 2 s will. other things equal, he 
solely determined by fluid pressure in the glomerular capillaries, 
and rate of flow of ihe fluid will be of no account. This conclu- 
sion is directly contradicted by the facts which prove beyond 
doubt that in perfusion experiments quantity nd at eo is, so 
things equal, directly dependent, not on rate of 
volume of the perfusing fluid alone, but on both eBoy ery te 


The only authors known to me who have previously advocated 
this hear are Lamy and Mayer (28). 
