THERAPEUTIC STUDIES ON IONS. 



73 



attempting to apply this principle, let us discuss first 

 of all the mutual effects of proteins and salts upon each 

 other. 



As is well known, proteins suffer a change in state in 

 the presence of many salts they are precipitated in solid 

 form. In the case of the salts of the alkali metals and 

 magnesium this precipitation does not occur until a cer- 

 tain, fairly high concentration has been reached. The 

 precipitate redissolves when the solution is diluted; the 

 process is, in other words, reversible. We will discuss 

 first of all the laws governing these reversible precipi- 

 tations. 



If the salts are arranged according to their power of 

 precipitating protein (as determined by the use of chem- 

 ically equivalent solutions), the following table is ob- 

 tained. + indicates that the protein is precipitated, 

 that it is not, n. s. that the salt has not been studied. 



Cations. The precipitating power increases > 



For one and the same anion the precipitating power 

 increases from magnesium toward lithium, and for each 



