RUSSELL: THE ACTION OF SALT SOLUTIONS. 385 
In an m/32 and m/16 KCI solution the contraction of the 
specimen was immediate and rapid and continued for about 
four minutes, when it gradually relaxed. But it never re- 
turned to normal. In m/64 KCl it was often indifferent, anc 
in m/32 KCl slight relaxation took place. An m/8 KCl 
strength proved toxic. 
It is interesting to note that in CaCl, solutions, after peri- 
stalsis ceased the contractions usually began at once, lasting 
from one to five minutes, and then in most cases the strip 
gradually returned to its original length. This tendency of 
contraction and then returning to its original length was most 
pronounced in m/32 solutions. The above results with NaCl, 
KCl and CaCl, agree with those obtained by Stiles. 
In MgSO, solutions, ranging from m/8 to m/32, intestinal 
strips relaxed, but relaxation was often more pronounced in 
an m/32 solution. Magnus in one of his papers states that 
BaCl, was a strong stimulus to the intestines and always 
causes a contraction. My results corroborate his statement, 
as is shown by the curves. The specimens did not reach their 
original length after the first contraction, and in each case the 
contractions were very pronounced. 
This work was pursued under the guidance of Dr. I. H. 
Hyde, to whom I am under great obligations for help and 
advice. ; 
The general conclusion drawn from the study of the above 
experiments is that the contraction of the intestinal strip of 
the frog is produced by solutions of BaCl, from m/64 to m/8; 
KCl from m/32 to m/16; CaCl, from m/64 to m/8 and alkaline 
Ringer solutions; while acid Ringer, NaCl from m/32 to m/8 
and MgSO, from m/32 to m/8, cause relaxation. These results 
are probably due to the action of the solution on the longi- 
tudinal muscle fibers in the frog’s intestine. 
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ALEXANDROWITSCH, 1904. Centralblatt, Bd. 18, s. 277. 
BAYLISS AND STARLING, 1899. Journal of Physiology, vol. 24, p. 99. 
BAYLISS AND STARLING, 1901. Journal of Physiology, vol. 26, p. 125. 
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DIxon, 1902. Journal of Physiology, vol. 28, p. 57. 
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