194 DRS CRTJM BROWN AND FRASER ON THE CONNECTION BETWEEN 



attention to the salts of the methyl derivatives of strychnia, brucia, and thebaia, 

 where the action is uncomplicated, we observe that they form a series in which 

 the fatal dose varies for each, while this dose in the case of the most active of 

 the three is considerably above that of curare, and greatly above that of curarina. 

 Besides, curarina has a characteristic colour reaction that belongs to none of 

 these bodies ; and the latter further prove this dissimilarity by each of them 

 possessing special colour reactions by which they may be distinguished from each 

 other. 



It is not only of great interest, but probably of some practical value, that five 

 new compounds should be found having the physiological action of curare. The 

 great difficulty of obtaining this substance has hitherto proved a serious barrier 

 to its therapeutical employment. Although none of the compounds that we 

 have shown to act as curare does are so energetic as that substance, three of 

 them — sulphate of methyl-strychnium, sulphate of methyl-brucium, and sulphate 

 of methyl-thebaium — are sufficiently so to fulfil all possible therapuetical require- 

 ments, and even to rank as powerful poisons. Moreover, they may be readily 

 obtained in a state of perfect purity, and, therefore, of constant strength; and, in 

 this respect, they possess a great advantage over curare. 



The six alkaloids we have examined may be divided into two classes, accord- 

 ing to the readiness with which they combine with iodide of methyl. The one 

 class includes strychnia, brucia, thebaia, and nicotia ; and the other, codeia and 

 morphia ; and the combination is much more easy with the former than with the 

 latter class. Without attaching any general significance to the occurrence, it 

 may not be altogether unworthy of being pointed out that in our experience, 

 therefore, the more active poisons are the more readily acted upon by iodide of 

 methyl. 



It is curious, though not unexpected, that the ordinary colour reactions of 

 the alkaloids are retained by their methyl derivatives. This may possibly prove 

 of some importance to the medical jurist ; and as these compounds are not preci- 

 pitated by alkalies, nor by the carbonates of the alkalies, some difficulty may be 

 met with in discovering their presence in cases of poisoning. 



