CERTAIN ALKALOIDAL PERIODIDES. 275 



solution be one containing free mineral acid and alkaloid, neutral alka- 

 loidal salt or free alkaloid and whether potassium iodide is present or 

 absent. 



Neither in aqueous solution nor in the absence of solvent is there 

 any marked tendency toward the formation of a definite compound or 

 compounds; on the other hand the reaction is apparently dependent on 

 the relative concentration of iodine, and the phenomena observed are 

 essentially those of equilibrium involving questions of vapor and osmotic 

 pressure. 



Moreover, it has been shown that it is not possible to recover with 

 thiosulphate the entire amoimt of "free" iodine which has combined 

 with the alkaloid. In the case of these alkaloids, therefore, and prob- 

 ably many other alkaloids as well, it is believed that the periodides 

 formed in aqueous solution differ both in mode of formation and in 

 constitution from the comparatively simple compounds demanded by the 

 commonly accepted theory of periodides. 



At present no theory is advanced concerning the constitution of these 

 various compounds and the mechanism of their formation, but an in- 

 vestigation of this question will be undertaken when an opportunity is 

 presented. 



102594 9 



