98 THE THEORY OF IONS 



relation between the cathartic effect of a salt and 

 the metallic portion of it. It is now known that 

 their effect in producing catharsis and diuresis is due 

 in part to the increased blood pressure they cause 

 and in part to their action upon the protein. The 

 cathartic and precipitating power parallel one 

 another in all of them. The heavy metals cause 

 precipitation in any concentration. 



The sulphocyanates are the last of the anion 

 series, and possess the properties of the group in the 

 highest degree. The Br ion has a well-marked 

 sedative effect ; the I ion has a multiplicity of 

 effects such as lowering of blood pressure, influencing 

 the metabolism of the thyroid gland, and the resolu- 

 tion of various inflammatory exudative products. 

 Williamson has shown that under the influence of 

 potassium iodide changes occur in the structure of 

 leucocytes ; in the small oxyphile leucocytes the 

 granules become gradually less distinct, and eventu- 

 ally the protoplasm appears perfectly homogeneous 

 and stains with eosin very feebly ; the larger eosino- 

 phile cells show no change whatever.* This effect 

 was also observed under the influence of pilocarpin 

 nitrate, sodium salicylate, carbolic acid, turpentine 

 and camphor. 



The sulphocyanates have been specially studied by 

 Pauli and Bruylants. The latter showed that there is 

 a relationship between the metabolism of the sulpho- 

 cyanates and the purin-bodies. Edinger has 

 shown that iodine and sulphocyanates exist in the 

 same places in the organism ; and that sulpho- 

 cyanates do not pass through the body even in the 



* Brit. Med. Jour., 1896, ii., 837. 



