116 Chapter VII 



The statement then that the kidney does not secrete after being 

 clamped is subject to certain limitations. If the word "secrete" 

 is used in the specialised sense it is true, but it can excrete if the 

 mechanical conditions are so altered as to promote increased 

 filtration. 



Another problem very similar to that which we have just studied, 

 in which the " call for oxygen " has been used as a test of the 

 activity of the cells, is furnished by the work of Brodie and Vogt. 

 The question was, Does the passage of water through the cells of the 

 intestine involve the activity of the intestinal epithelium ? 



First let me consider cases in which the fluid is passing from the 

 lumen of the intestine to the blood, i.e. cases of absorption from the 

 intestine. 



When physiological saline is placed in the intestine and thence 

 finds its way into the blood, work is not necessarily performed in 

 order to satisfy the energy conditions of the system. In practice 

 of course there is likely to be some, just as some expenditure of 

 energy is necessary to drive even the most facile bicycle along the 

 most level and perfect track. The absorption of distilled water is 

 still more interesting for then work might actually be done on the 

 system. There is therefore no a priori reason for supposing that 

 the absorption of these fluids from the intestine either is or is not 

 a process involving the activity of the cells. 



The simple way of putting the matter to the test was to deter- 

 mine the effect on the oxygen used up by the intestine. In practice 

 the experiment is far from simple, but in the hands of a physiologist 

 who probably has no superior alive at the present time in the type of 

 manipulative procedure involved, the experiments were satisfactorily 

 carried out. The result was an increase in the oxygen consumption, 

 which clearly showed that the absorption of water was an active 

 process. The following are the data of a couple of experiments from 

 Brodie and Vogt's paper. 



1. Absorption of Physiological Saline. 



11.25. Operation completed. 



11.45. B.F1. = 46-875 c.c. per min.= 0-433 c.c. per grm. per min. B.P. =95. 



11.49. Blood samples taken, Stage I. 



11.55. Injection of 100 c.c. of warm sodium chloride solution, 0'93 / . 



11.58. Rate of absorption 0'4 c.c. per min. 



12.03. ,, ,, I'O c.c. per min. 



12.06. B.Fl. = 46-875 c.c. per min. =0'433 c.c. per grm. per min. B.P. =130. 



