OBSERVATIONS ON THE INTRACAPSULAR PRESSURE AND THE MOLECULAR CONCENTRATION OF THE RENAL CAPSULAR FLUID IN NECTURUS

Abstract

The pressure in the lumen of the capsules of functioning glomeruli in Necturus ranges from 1 to 57 mm. of water. Barger''s vapor tension method for determining molecular concentration is applicable to blood serum. The molecular concentration of the glo-merular fluid was higher than that of the serum in each of 12 experiments. The glomerular membrane actively secretes a solution more concentrated than the plasma. This process is not incompatible with a simultaneous filtration; it is probable that the latter process is operating, but this has not yet been completely proved.