I20 P. G. Stiles and C. S. Milliken 



"physiological" mixtures. At the conclusion of that paper we 

 questioned whether it might not be possible to find a mixture of 

 lithium chloride with some other salt which should still more closely 

 approach the normal fluid in its conserving properties. When 

 we expressed this hope, we had already made some tentative experi- 

 ments with suggestive results. These we have since repeated and 

 extended, and our observations may now be outlined. 



Some time ago we investigated the duration of irritability and 

 the working capacity of muscles immersed in solutions of magne- 

 sium chloride. We found that the loss of excitabihty is rapid, 

 and that two or three hours in such a bath makes the gastrocne- 

 mius unresponsive to the strongest stimulation. Thus solutions of 

 magnesium chloride alone are distinctly unfavorable to the muscle 

 protoplasm. However, we were led to test mixtures of the chlo- 

 rides of lithium and magnesium (with the former in large excess), 

 and to compare the records written by muscles treated with these 

 mixtures with those obtained from companion muscles in lithium 

 chloride alone. It seemed not unlikely that these combinations 

 might prove somewhat superior to the straight hthium chloride, 

 as well as vastly better than the unmixed magnesium chloride. In 

 the current phraseology we looked for an antitoxic action on the 

 part of magnesium. 



The specific influence of magnesium salts upon various living 

 tissues has not been sufficiently investigated. At the time of this 

 writing* there has appeared the first of a promised series of papers 

 by Meltzer and Auer,^ which will doubtless make much new and 

 exact information available. As these writers point out, the con- 

 spicuous property of magnesium salts in large quantity is a depres- 

 sing or paralyzing one, and they suggest that the physiological role 

 of these salts, which are somewhat abundant in animal cells and 

 fluids, is inhibitory. If this is the case, there is a closer relation- 

 ship between magnesium and potassium than between magnesium 

 and calcium. It should be easy to define the comparative effects 

 and the antagonisms of these salts by experiments with plain and 

 cardiac muscle, and we have undertaken work along these lines. 



In the present contribution we shall confine ourselves to the 



♦November, 1905. 



