EFFECT ON ORGANIC FUNCTIONS 21 



through animal membranes has also been studied 

 from the ionic standpoint by Rudolf Hober.* He 

 has shown that the salts absorbed from the small 

 intestine into the blood are hypertonic, isotonic, and 

 hypotonic ; and that isotonic salts are absorbed at 

 different rates. He used solutions so dilute that the 

 salts were almost completely dissociated electro- 

 lytically, and he found that they behaved differently 

 according to the proportion of the contained ions 

 or the ionic concentration. The cations K, Na, and 

 Li, were absorbed with almost equal rapidity ; NH 4 

 and urea more quickly ; Ca more slowly, and Mg 

 slowest of all. Of the anions, Cl was absorbed most 

 rapidly, then followed in order Br, I, N0 3 and S0 4 . 

 The absorption of Ba could not be observed because 

 of its injurious action on the mucous membrane. 



Various other biological functions have also been 

 considered from the standpoint of the ionic theory, 

 For instance, chloride of sodium is a common and 

 almost essential constituent of ordinary human 

 food, and it has been asserted that its presence in 

 food provokes or aids the secretion of hydrochloric 

 acid in the stomach. Now, it is not proved that 

 the stomach is impermeable to CF ions ; but Beurath 

 and Sachs f consider they have proved that the acid 

 secretion has no relation to the presence or absence 

 of chloride of sodium in the food ; that the absence 

 of Cl ions from the food does not prevent the forma- 

 tion of HC1 in the stomach ; nor does the introduc- 

 tion of a chlorine-free solution into the stomach 

 abolish the secretion, which comes from the blood. 



* Pfliiger's Archiv, 1898, Ixx., 624. 

 t Ibid., 1905., cix., 466. 



