The Inhibitory Effect of Magnesium. 95 



the aorta of the surviving rat and the oozing blood was replaced by 

 the injected fluid. These injections have been continued in the 

 study of rat-mouse parabiosis, but in the injections so far attempted 

 our technique has not been sufficiently satisfactory to make the 

 results conclusive. 



59 (469) 



A demonstration of the inhibitory effect of magnesium upon 

 normal and artificial peristalsis of the stomach 

 and duodenum. 



By DON R. JOSEPH and S. J. MELTZER. 



[From the Department of Physiology and Pharmacology of the 

 Laboratories of the Rockefeller Institute for Medical 

 Research^ 



Some years ago J. B. MacCallum 1 made the statement that 

 purgation can be brought about by subcutaneous or intravenous 

 injection of magnesium sulphate. He ascribed the effect to the 

 stimulation of nerve and muscle tissue of the intestines by this 

 salt, which thereby caused increased peristalsis. 



In a paper by Meltzer and Auer 2 it was stated, however, that 

 magnesium salts not only do not cause peristalsis, but directly in- 

 hibit it when normally present or even when aggravated by barium 

 or physostigmin. 



In opposition to this statement it was asserted in a paper by 

 S. A. Matthews and D. E. Jackson 3 that after injection of mag- 

 nesium sulphate the peristalsis shows no especial departure from 

 the normal and barium and physostigmin show their usual action. 



In order to obtain unbiased and incontestible evidence, the 

 question was studied now by the graphic method. We employed 

 for this purpose the following procedure. Rabbits only were used. 

 A laparotomy was performed under anesthesia and a soft rubber 

 catheter bearing a thin walled rubber ballon at its end, was intro- 

 duced through an incision into the stomach and then pushed 

 through the pylorus into a deep place in the duodenum. 

 Another similar ballon was left in the stomach. All the incisions 



1 Anter. Jour, of Physiol., 1903, x, 101. 



2 Amer. Jour, of Physiol., 1 906, xvii, 313. 

 * A?ner. Jour, of Physiol., 1907, xix, 5. 



