1148 PHYSIOLOGY 



diuresis, the serum contained 0-547 per cent, chlorine and 0-259 per cent, 

 sulphate, while the urine contained 0-372 per cent, chlorine and 0-546 per 

 cent, sulphate. In the second, in which the rabbit was killed when the rate 

 of the urinary flow had considerably diminished, the serum contained 0-493 

 per cent, chlorine and 0-191 per cent, sulphate, while the urine contained 

 094 per cent, chlorine and 2-0 per cent, sulphate. These results are illus- 

 trated in Fig. 536. 



15 30 45 60 75 90 105 180 135 



FIG. 536. Curves showing excretion of urine (thick line), of sulphate molecules 

 (^Q, thinline), and of Cl molecules (^., dotted line), after injection of 50 c.c. 



of a solution containing 1 -775 grm. Cl and 4-8 grm. 804 per 100 c.c. The black 

 line along the base marks the duration of the injection. (CusHNY.) 



The difference between the two salts can be made still more striking if 

 the process of resorption be augmented by increasing the pressure within 

 the tubules by partial obstruction of one ureter. Thus in one experiment, 

 where diuresis was produced by the injection of 30 c.c. of a solution con- 

 taining 5-85 per cent. NaCl + 14-2 per cent. Na 2 S0 4 , the right ureter was 

 partially clamped so as to make the right kidney secrete against a pressure 

 of 31 mm. Hg. The following results were obtained : 



We must conclude that the tubular epithelium possesses the power of 

 modifying the glomerular transudate not only by the absorption of water 



