A New Conception of the Glomerular Function. 



577 



The diuresis at the time the kidney pedicle was ligatured was 1 c.c. per 

 minute. 



From the formula for the flow of liquids along narrow tubes 

 p = 8Z?7/7rr 4 times flow in cubic centimetres per second dynes per square 

 centimetre, 



where / is the length of the tubule in centimetres, 



7) is the coefficient of viscosity, and 



r is the radius of the tube in centimetres. 

 Taking t) as 719 x 10~ 5 , the coefficient of viscosity of water at 35° C, we 

 have 



8x719x10-5 1 1 inl6 I , ... 



p = . — . -—ttt^ • 10 • —. dynes per square centimetre, 



r 7T 60 142000 . 



r being now expressed in microns ; or 



p = n , ? X ?1^ X7 ) , > , • 10 7 . 4 mm. Hg. = 1-611 x 10 4 x 4 mm. Hg. 

 F 22x 6x 142x1333-2 r l ° r 4 ° 



Consequently, for a flow of 1 c.c. per minute, 



li. mm. Hg. 



p per centimetre of tubule, when r = 4*5, = 39-29, 



r = 5, = 25-78, 

 r = 6, = 12-43, 

 r = 8, = 3-93, 

 r = 9, = 2-46. 



Hence pressure-head required for — 



mm. Hg. 



Proximal convoluted tubule = 1*2 x 1243 = 14-916 



Loop of Henle — ■ 



Descending limb = 0-9 x 25-78 = 23-212 



Ascending limb = 9 x 39 29 = 35'361 



Distal convoluted tubule = 2 x 2-46 = 0-492 



Collecting tubule = 2-2 x 3"93 = 8-646 



Total pressure-head 82-627 



In the case of the second kidney, with 125,000 tubules, the measurements 



were : — Length. Diameter. 



cm. ix. 



Proximal convoluted tubule l'O 12 



Loop of Henle — 



Descending limb - 8 10 



Ascending limb - 8 10 



Distal convoluted tubule 0'2 18 



Collecting tubule 2-0 8 



And, with a diuresis of - 85 c.c. per minute, the pressure-head required works 

 out to 74 - 1 mm. H^. 



