1196 



PHYSIOLOGY 



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

 taining 5-85 per cent. Nad + 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 

 but also by the absorption of .dissolved constituents, and that the relative 



15 -^0 45 60 75 90 (OS \20 135 



Fia. 547. Curves showing excretion of urine (thick line), of sulphate molecules 



^\ thin line), and of Cl molecules , . dotted line), after injection of 50 c.c. 



96 \o5*5 



of a solution containing 1-775 grm. Cl and 4'8grm. S0 4 per 100 c.c. The black 

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



permeability of the cells to the constituents is at any rate one factor in deter- 

 mining the substances absorbed. It is not however the only factor. The 

 function of the kidney is to preserve the normal constitution of the body 

 fluids by turning out those substances which are abnormal or present in too 

 great an amount. The behaviour of the tubule cells with regard to any given 

 substance will therefore depend to a certain extent on the previous nutritive 

 history of the body. 



If for instance, in consequence of the administration of sodium chloride 



