40 KANSAS UNIVERSITY SCIENCE BULLETIN. 



contractions as a rule is at first decreased in all strengths but 

 the m/100; m% is toxic to heart and respiratory activity, 

 though usually the respiratory rhythm continues for five to 

 twenty minutes after the heart has ceased. 



A summary of some experiments that were undertaken to 

 study what salts counteracted the toxic influence of KCl solu- 

 tions is shown in table lib, and curves 10, 11, 12 and 13 illus- 

 trate a few of the experiments. 



Curve 10 records the antitoxic effect of an m% NaCl solution. 

 The rate of the heart's action was 36, that of the respiratory 

 26. At 10 :05 m% KCl was injected ; within a few seconds the 

 heart action became irregular and respiration rapid, then ir- 

 regular, with prolonged expiratory phases. Blood pressure 

 fell. At 10 :15, an injection of m% NaCl was followed in a few 

 seconds by regular and strong cardiac and respiratory con- 

 tractions, which in ten minutes were quite normal, but the 

 force of the heart-beat was stronger. In other experiments 

 the toxic effect of an m% KCl was quickly counteracted by an 

 m/8 NaCl solution. 



Curve 11 shows the favorable influence of CaCh with or pre- 

 ceding a KCl solution; m/4 KCl following m/4 KCl+m/32 

 CaCk shows a decrease in force of heart and respiratory ac- 

 tivity, and a toxic m% KCl following a mixture of m% KC1+ 

 m/32 CaCk shows, in addition to a decrease in rate, a marked 

 decrease in force, but in twenty minutes the heart and respira- 

 tory rhythm is almost normal. The CaCk evidently proved 

 antitoxic, and with KCl enhances the force of both respiratory 

 and cardiac action. 



Curve 12 also shows that a dose of m/4 CaCb that preceded 

 an m% KCl and m/1 KCl counteracted their toxic effects. 



Curve 13 : After CaCk m%, blood pressure stood at 14 mm., 

 heart action at 24, respiratory action at 36. When m% KCl 

 was injected, pressure fell to 2 mm, heart to four contractions 

 and respiration increased to 42. At the end of two minutes 

 pressure was again 14, heart and respiratory rate had in- 

 creased, though shallow. At the end of five minutes, pressure 

 and action of heart and respiration were quite normal, but 

 respiratory rate more rapid. This shows that when stronger 

 solutions of Ca are injected, and the blood is in excess of the 

 normal, it counteracts the toxic effect of m% solution of KCl 

 quicker and the toxicity is less marked on respiratory than 



