TOXICOLOGY AND PHARMACOLOGY 411 



with narcotics (morphine, chloral, ether, urethan), no diuresis de- 

 velops, and on the other hand the absorption of water from the in- 

 testines is unimpaired. This is explained by the fact mentioned 

 (p. 338), that such narcotics inhibit the oxidizing processes in the 

 organism, which results in a greater fixation of water ("acid swell- 

 ing"). 



What holds for electrolytes is also true for nonelectrolytes. We 

 have recognized in urea a substance which greatly aids diffusion 

 through jellies (see p. 55) and which opens through the hydrogel 

 paths for itself and other substances; as a matter of fact it acts as 

 a diuretic. I wish to mention some additional facts concerning 

 ammonium salts and the cleavage products of protein. All the evi- 

 dence (see pp. 80 to 82) is in favor of the view that the action of 

 the cations and of the anions of an electrolyte is antagonistic and that 

 they mutually counteract a portion of their own activity. Thus NH 4 

 seems to oppose the precipitating and dehydrating action of S0 4 , 

 citrate, and tartrate anions to a greater extent than K and Na (see 

 the Series III of our group). If we bring this into relation with 



analogous action of urea CO / ' we may in general attribute to 



\NH2 



the NH 2 and NH 3 groups the property of aiding diffusion and we 

 also understand the ease with which protein cleavage products are 

 absorbed, for they occur in the intestines largely split into substances 

 with free NH and NH 2 groups. 



MARTIN H. FISCHER explains the diuretic action of digitalis prepa- 

 rations and of caffein as follows. They increase the strength and 

 frequency of the pulse, increase the utilization of oxygen and thus 

 the blood supply of the kidneys is increased and the "free" water in 

 the blood is increased and may be excreted. This agrees with the 

 results of SOBIERANSKI, HIROKOWA and GRUNWALD who found that 

 the diuretic action of caffein, theobromin and diuretin depended on 

 their interference with reabsorption. 



GRUNWALD was able to show, for instance, that rabbits on a 

 chlorin-free diet when treated with theobromin finally perished for 

 want of chlorin. The chlorin removed from the body by ultrafiltra- 

 tion was not restored by reabsorption. 



Purgatives. 



If we wish to explain the action of purgatives we must first re- 

 view the processes in the intestines. The intestine is the place where 

 secretion and absorption occur. The volume of the secretion of the 

 salivary glands, the stomach, bile, pancreas and intestine is, accord- 



