1871.] 



History of the Opium Alkaloids. 



9 



hydric sulphide on iodine and water : in the dilute acid thus got, iodine 

 was dissolved, and the whole digested at a very gentle heat with phosphorus, 

 more iodine solution being added from time to time ; finally the whole was 

 distilled several times from potassium iodide. A colourless acid of sp. gr. 

 1 '7-1 '75, and containing 50-55 per cent, of HI, was thus obtained, and 

 preserved colourless by keeping a stick of phosphorus in the bottle. The 

 codeia used in these experiments was part of a further supply most libe- 

 rally presented by Messrs. Macfarlane, of Edinburgh. 



On heating on the water-bath a mixture of 10 parts codeia, 30 to 50 of 

 this acid, and 1 of phosphorus, the evolution of methyl iodide is noticed in 

 a few minutes ; simultaneously the liquid becomes brown, indicating the 

 separation of free iodine ; after two or three hours the brown colour dis- 

 appears, and the evolution of methyl iodide ceases. If the liquid be heated 

 to gentle ebullition, at first the same effects ensue, but more quickly ; the 

 resulting product, however, varies in composition according to the tempe- 

 rature at which the reaction was effected. 



In one experiment 55 grammes of codeia yielded by condensation 22*5 

 grammes of methyl iodide, the theoretical yield being 24*6 from crystallized 

 codeia, C 18 H 21 N0 3 , H 2 ; hence upwards of 90 per cent, of the theoretical 

 yield was obtained. In order to prove the elimination of part of the 

 carbon in the form of methyl iodide, 4*3045 grammes of codeia, dried at 

 140°-150° C, was heated to gentle ebullition with 30 grammes of 55 per 

 cent, hydriodic acid and about 2 of phosphorus ; the vapours evolved 

 were passed through a flask to condense aqueous vapour, and then through 

 a combustion-tube filled with red-hot lead chromate, the C0 2 produced 

 being absorbed in the usual way, an aspirator being attached at the far end 

 so as to create a diminished pressure throughout the apparatus, and thus 

 guard against loss of methyl-iodide vapour by leakage at any of the nume- 

 rous corks and joints*. After three hours a current of pure oxygen was 

 led through the apparatus, to sweep out the last traces of methyl-iodide 

 vapour from the flasks and ensure the perfect combustion of deposited 

 carbonaceous particles. 



4*3045 grms. codeia thus gave 0*617 grm. C0 2 . 



0*3720 grm. codeia, burnt in the usual way, gave 0*9830 C0 2 . 



Found. Calculated, 



(A) Percentage of carbon evolved as CH 3 I 3*91 4*013 



(B) „ „ in codeia used . . 72*07 72*241 



Ratio of A to B 



3*91 _ 1 

 72*07 18*2 



4*013 1 



72*241 18 



In another experiment, not carried to a complete conclusion, the C0 2 col- 

 lected represented 3*7 per cent, of the codeia used. 



The methyl iodide produced was found, after washing with water, dry- 



* This device may be applied with advantage to the ordinary processes for combus- 

 tion, blowing out of the tube as well as loss by traces of leakage being thus avoided. 



