34 KANSAS UNIVERSITY SCIENCE BULLETIN. 



tion (see curve 1) increases the force and blood pressure but 

 leaves the rate of the heart and respiration unaltered. 



An m/1 solution (curve 2) causes a rise in blood pressure 

 and force of heart's rhythm at once, which usually continues 

 for about twenty minutes. But the force and rate of respira- 

 tion is either unchanged for one to two minutes and then de- 

 creases ; or may, as does the heart rate, first decrease and then 

 return to normal. 



Following the injection of a 2m NaCl solution (curves 3 and 

 4) the blood pressure increased for about five minutes, then 

 became normal. The rate and force of the heart and respira- 

 tory movements decreased for one to twenty-five minutes ; but 

 in many cases the force of the heart's activity first decreased 

 for one to two minutes and then increased, or increased as the 

 blood pressure rose. In every instance the systole and inspira- 

 tory phases were prolonged above normal with a 2m NaCl 

 solution. 



A resume of the NaCl experiments shows that injections of 

 4 cc. per kilo fish of m/64 to m/8 solutions are as a rule prac- 

 tically indifferent; m% stimulates the force of heart and res- 

 piratory activity and raises blood pressure for from one to 

 five minutes, but is usually indifferent to rate; m/1 increases 

 the force of the heart's action and also blood pressure, but the 

 rate and force of respiratory activity differs in that they may 

 for one minute remain normal, then decrease; or may, as does 

 the heart rate, decrease for one to three minutes before re- 

 suming again the normal activity ; 2m decreases rate and force 

 of heart and respiration, but the heart's force is often increased 

 after one to two minutes' decreased action. The blood pressure 

 is raised during the first one to five minutes, then falls. 



It might be concluded that the blood salts can be slightly in- 

 creased by 4 cc. per kilo m/64 to m/8 without stimulating or 

 inhibiting either of the three functions that are considered, 

 and that equilibrium of the osmotic pressure is rapidly estab- 

 lished. On the other hand, m% stimulates the force of both 

 heart and respiration. I infer that its effect is directly upon 

 the nerve centers for one to five minutes, before the attraction 

 of water to the blood establishes equilibrium. An increase to 

 m/1 has a stimulating effect only upon the force of the cardiac 

 center, thereby increasing also the blood pressure, but 



