A CONTRIBUTION TO THE GENERAL PRINCIPLES OF 



THE PHARMACODYNAMICS OF SALTS AND DRUGS.* 



A. P. MAT HEWS. 



(From the Laboratory of Physiological Chemistry of the University of Chicago.) 



THIS paper is a continuation of those already published, 1 which 

 have had for their object the investigation of the means by which salts 

 and drugs influence the processes going on in living matter, and thus 

 produce the phenomena of stimulation and depression. 



PART I. PHARMACODYNAMIC ACTION DUE TO IONS. 



The cause of the pharmacological action of salts upon protoplasm 

 has been the subject of numerous investigations, but until the develop- 

 ment of the ionic theory these investigations had led to no further 

 result than to show that in groups of similar metals the heavier were 

 frequently the more poisonous. The application of the ionic theory 

 first brought some order into this part of pharmacology. The work 

 of the American investigators Kahlenberg and True 2 and Heald, con- 

 firmed as it has been by Kronig and Paul, Hober, True, and many 

 others, has shown in the clearest manner that there is a close paral- 

 lelism between toxicity and the state of ionization of many of the 

 metals, so that these authors conclude that the pharmacological action 

 of any salt solution is a function, in large measure at least, of the ions 

 into which the salt dissociates. 



This general conclusion is, in my opinion, as firmly established as 

 is the conclusion that the chemical reactions of such solutions are due 

 to the ions they contain. Indeed, the conclusion is a necessary result 

 of the ionic theory, since the chemical reactions in protoplasm do not 

 differ in nature from those going on elsewhere ; and if salts enter into 

 other chemical reactions by their ions, they probably enter also in the 

 same manner into the reactions of protoplasm. 



But while this general theory is a great step forward, it stumbles 

 against the objection that many compounds profoundly affect proto- 



* Received for publication March 23, 1906. 



1 MATHEWS, Amer. Jour. Physiol., 1904, 10, p. 291; 1904, 11, p. 455; 1905, 14, p. 204; 1905, 12, 

 p. 421; 1904, n, p. 238. 



KAHLENBERG AND TRUE, Botanical Gazette, 1896, 22, p. 91. 



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