ABNORMAL IRRITABILITY PRODUCED BY SALTS 695 



irritability ; neither did sodium acetate nor other salts whose 

 anions form soluble calcium compounds. 



But the sodium salts whose anions precipitate calcium 

 promptly produce these reactions. NaFl, Na 3 CO s , Na 2 HPO 4 

 sodium oxalate, sodium citrate, 1 sodium tartrate give the 

 contact reaction in a dilution of 1 gram-molecule in 8 or 10 

 liters of water or even less. NaHCO 3 gives the reaction but 

 requires a higher concentration, e. g., 1 gram-molecule in 4 

 to 5 liters of water. If we put the muscle into a solution of 

 Na 3 PO 4 , it goes at once into a powerful tetanus. This 

 tetanus may be partly or wholly due to the high concentra- 

 tion of HO ions in this solution. When a muscle goes into 

 tetanus in a solution, we cannot, as a rule, demonstrate the 

 contact-reaction. Thus I have never succeeded in producing 

 contact-reaction by a Na 3 PO 4 solution. NaH 2 PO 4 does 

 not cause contact -irritability, but this is in harmony with 

 our general result. 



The HO and H ions deserve special attention. In my 

 experiments on rhythmical contractions I found that while 

 they are not able to produce rhythmical contractions directly, 

 they accelerate the beginning of these contractions in the 

 presence of Na ions. In addition to such a catalytic action 

 common to both the HO and H ions, the former have another 

 effect which they do not share with the H ions. The muscle 

 produces constantly H 3 CO 3 and possibly other acids. These 

 acids will increase the solubility of Ca salts and increase 

 the number of Ca ions in the tissues. An addition of HO ions 

 will counteract this effect. 



It is due to the presence of free HO ions that solutions 

 of Na valerianate and Na formate give rise to a slight degree 

 of contact -irritability in muscle, although calcium formate 

 and calcium valerianate are soluble. If we diminish the 



iThe citrates require an alkaline reaction for the precipitation of calcium 

 This condition is fulfilled in the fresh normal muscle. 



