208 On substituting Iodine for Hydrogen in Organic Compounds* 



pyromeconic acid, now becomes obvious. It is represented by 

 the following equation :— * 



CIO H4 06+8ICl+8H0=C«H'» P 06H-4COH8HCI. 



This being the mode of its formation, it seemed probable that 

 meconic and comenic acids, which differ from pyromeconic acid 

 only by the elements of carbonic acid, would yield the same sub- 

 stance when acted on by chloride of iodine. Accordingly, I 

 have found that it is immediately produced with all its charac- 

 teristic properties from these acids, by the same process. The 

 Telations of this substance to meconic and pyromeconic acids, are 

 of a very remarkable character, and cannot at present be di- 

 stinctly brought out. It obviously belongs to the same class as 

 the very curious product obtained by Cahours, by the action of 

 bromine on citric acid, and which he has called bromoxaform. 

 According to this chemist, when bromine is added to citrate of 

 potash, effervescence takes place from the evolution of carbonic 

 acid, and on the addition of potash, an oily matter is thrown 

 down, which consists of three substances, one bromoform, the 

 other a crystalline solid, bromoxaform, and the third apparently 

 an accidental product, for it is obtained in too small quantities 

 to admit of examination. It can scarcely be doubted that brom- 

 oxaform would be the only ! product, if the action could be 

 properly moderated, and that the bromoform is a secondary pro- 

 duct of the former substance, from which indeed it is readily 

 obtained by treatment with caustic potash. If this be the case, 

 the decomposition of citrate of potash would be quite analogous 

 to that of pyromeconic acid, as represented in the equation — 



QX1 H5 K3 O" + 2H0 + Br" = C« HBr* O^ + 600^ + 3K Br + 6HBr. 



Citrate of potash . Bromoxaform . 



The relation which these curious substances bear to their 

 parent acids is very obscure, and cannot be elucidated without 

 further experiments. In regard to iodomecone, the small quan- 

 tity in which I was able to obtain it, has prevented my following 

 out its decompositions as I could have wished, but I propose ex- 

 tending this investigation to some of the stronger acids, by 

 which means some light may probably be thrown upon the con- 

 stitution of these bodies. 



It was my desire to have extended my examination of the 

 iodine substitution products obtained by chloride of iodine to 

 some other substances. As yet, however, I have only tried 

 codeine; but the instability of the compound produced has 

 occasioned such difficulties, that I have hitherto been unable to 



