IONS AND LIPOIDS 103 



between the ion and the protein. This is important 

 because of their affinity for the musculature of the 

 heart and bloodvessels, and the processes of calcifi- 

 cation, atheroma and arterio-sclerosis which depend 

 upon such affinity. The firm union of the ion and 

 protein takes place even before the precipitation 

 limit is reached. But the precipitating power of 

 the metallic ion is markedly depressed by the anion 

 Br, still more by I, and most of all by the sulpho- 

 cyanate anion, which also has a strong affinity for 

 the protein. A firm bond can be formed by Ca even 

 in the presence of iodide or sulphocyanate anions. 

 The calcium-iodide-protein is however much more 

 soluble than calcium-carbonate or phosphate-pro- 

 tein. The I ion not only forms a soluble protein- 

 calcium combination, but by its presence inhibits 

 or prevents the formation of insoluble calcium- 

 protein combinations and favours the excretion of 

 the metallic ion. This is the basis for the clinical 

 observation that the continued use of iodides is 

 useful in the treatment of arterio-sclerosis and will 

 retard its course. 



It has thus been established by experiment and 

 clinical observation that the iodides and sulpho- 

 cyanates bring about the excretion of lime, lead and 

 mercury from the human system by forming ion- 

 protein compounds which readily go into solution. 

 Therapeutics may therefore continue to speak of 

 the alterative and resolvent effect of drugs, and is 

 presumably correct in speaking of such actions as the 

 effects of ions upon the colloids. Indeed the action 

 of all salts is the effect of its ions upon the colloids 

 or crystalloids in the organism. Most of the alka- 



