Mat 30, 1913] 



SCIENCE 



845 



ON THE COLLOID-CHEMICAL ACTION OF THE 

 DIURETIC SALTS ^ 



This paper reports a further series of ex- 

 periments on rabbits which show that the col- 

 loids of the cells and of the juices which hathe 

 them (blood and lymph), and the state in 

 which these exist determ,ine in the m,ain the 

 amount of water such cells and hody fluids 

 hold under both normal and abnormal con- 

 ditions. 



The maintenance of a urinary secretion de- 

 pends upon two factors, first, upon a supply 

 to the ls;idney of " free " water out of which to 

 make urine, and second, upon the ability of 

 the kidney cells to do the work necessary in 

 transferring the water from the blood into the 

 uriniferous tubules. Urinary secretion may 

 fail through interference with either of these 

 factors. 



The intravenous injection of any amount of 

 blood, blood serum, or a hydrophilic colloid in 

 which all the water is bound to the colloid, is 

 followed by no increase in urinary secretion. 

 This is because no " free " water is given. 

 The same amount of water when given " free," 

 as in the form of a saline solution, is followed 

 by a prompt increase in urinary flow. 



When equal amounts of sodium chloride 

 solution are injected we get increasingly 

 greater amounts of urine with progressive in- 

 crease in concentration of the salt. This is 

 because the salt dehydrates the body tissues, 

 and the " free " water thus obtained is added 

 to that which is being injected. The salt 

 owes its action as a diuretic primarily not to 

 any effect upon the kidney, but to its action 

 in dehydrating the colloids of the whole body. 



When equal amounts of equimolecular solu- 

 tions of different salts are injected it is found 

 that the order in which these produce diuresis 

 is the same as the order in which they dehy- 

 drate (protein) colloids. Thus in a series of 

 chlorides the metals arrange themselves in the 

 following order, in which that most powerful 

 in producing a diuresis is named last : sodium, 

 magnesium, strontium, calcium. In a series 

 of sodium salts the acid radicals arrange 



' A preliminary communication. 



themselves as follows: chloride, nitrate (?), 

 bromide, iodide, acetate, phosphate, sulphate. 

 The greatest diuresis of all is produced by a 

 salt which is made up of a powerfully dehy- 

 drating base with a powerfully dehydrating 

 acid, for example, magnesium sulphate. 



The diuretic action of these different salts 

 parallels completely their dehydrating effect 

 upon (protein) colloids, a fact which again 

 indicates that they owe their action primarily 

 to their effect upon the body as a whole, act- 

 ing as diuretics only as they furnish a word- 

 ing Mdney " free " water. 



The experiments also betray no evidence of 

 an antagonism between monovalent salts such 

 as those of sodium, and bivalent salts such as 

 those of calcium, strontium, etc. Such salts 

 act synergetically, not antagonistically, in 

 physiological reactions, just as they do in test- 

 tube experiments on simple protein colloids. 



It is impossible to explain these salt effects 

 upon any osmotic basis, for there exists not 

 even the grossest parallelism between the 

 physiological effect and the osmotic pressure 

 of the solutions employed. Our critics have 

 maintained that osmotic phenomena dominate 

 the picture of absorption and secretion in 

 " living " tissues. They have grown willing 

 to grant that the colloidal theory is operative 

 in " dead " tissues. In the described experi- 

 ments the osmotic element can hardly be 

 found; the colloidal element appears plainly 

 in every one of them. It is needless to add 

 that our rabbits were alive. 



The detailed laboratory findings upon which 

 this article is based have been submitted for 

 publication in the Kolloid Zeitschrift. 



Martin H. Fischer 

 Anne Sykes 



ElCHBEKG LABOEATOEY OF PHYSIOLOGY, 



Univbesity of Cincinnati, 

 April, 1913 



SOCIETIES AND ACADEMIES 



THE AMEEICAN MATHEMATICAL SOCIETY 



The one hundred and sixty-third regular meet- 

 ing of the American Mathematical Society was 

 hald at Columbia University on Saturday, April 

 26, extending through the usual morning and 



