﻿PHAEMACOLOGICAI; ACTION OF URANIUM 



9 



any light upon the question of the similarity or the difference in 

 the methods by which cyanides and nraninm prevent the coagula- 

 tion of blood. It is to be noted, however, that uranium does not 

 inhibit the action of these ferments^. 



It was shown by Collingwood^ that if a two per cent solution 

 of disodium-hydrogen-phosphate (NaoHP^) be added to blood (in 

 any amount up to an equal volume) and the free calcium ions be 

 thus precipitated out, the blood would still clot, but a somewhat 

 longer time (one-half hour) wa-s required for the completion of the 

 process than was necessary in the case of normal blood. The usual 

 test for uranium is the formation of a precipitate when a phos- 

 phate solution is added to a solution containing uranium. It seemed 

 that this coincidence might furnish an opportunity to determine 

 something concerning the action of uranium. Since sodium-urani- 

 um-tartrate does not precipitate dilute calcium chloride solutions, 

 we should expect some sort of proteid combination to be formed 

 by the uranium, or, the presence of the metal may in some way 

 check the action of the ferments. At any rate, if it should be pos- 

 sible to add sufficient phosphate to precipitate all the free calcium 

 in the blood (and still leave an excess of phosphate ions free (?) 

 in the plasma), then the addition of an equal volume of a two per 

 cent solution of disodium-hydrogen-phosphate to blood which has 

 been prevented from clotting by the previous addition of the small- 

 est effective quantity of uranium might cause clotting to take place, 

 this, however, being dependent upon the nature of the uranium 

 action. If it were merely inhibiting the ferments by its presence 

 in solution, clotting ought to occur. If it were loosely bound to 

 some proteid element, clotting would probably occur. If it should 

 be firmly combined with some proteid absolutely essential to clot 

 formation, clotting would probably not occur. 



A series of experiments were carried out to test this point. 

 Perfectly fresh blood was obtained from etherized dogs and was 

 used immediately after withdrawal from the right femoral artery. 

 It, was found that if a small amount (one-tenth volume of two per 

 cent solution) of sodium-uranium-tartrate be added to fresh blood 

 and clot formation be thereby prevented, then the addition of a 

 two per cent solution of disodium-phosphate (NaoHPO^) in any 

 amount up to one-half of the total volume would not cause clot- 



Chittenden (Joe. cit.) found in general that an extremely small amount of 

 uranium increased, while more decreased the activity of the digestive ferments, the 

 reactions varying somewhat with the different uranium salts used. 



3 Collin^ood, Journal of Physiology, XXXVIII, (1909), Proceedings of the 

 Physiological Society, Ixxix. 



