THE CHEMISTRY OF STROPHANTHIDIN. 5 



passed slowly into brown with patches of green, and then the whole gradually became 

 very pale brown. 



8. Strong sulphuric acid and chlorate of potassium produced a crimson colour, which soon 

 became pale reddish -yellow. 



9. Phosphomolybdic acid very slowly developed a pale greenish-blue colour. When an 

 alkali was added along with or after the phosphomolybdic acid, a blue colour was imme- 

 diately developed. 



10. After contact with strong sulphuric acid had developed the usual orange-red colour 

 in powdered strophanthidin, exposure to the vapour of bromine rapidly deepened the 

 colour to a dark salmon-red, in which the undissolved ' particles of strophanthidin 

 appeared black ; and, soon afterwards, the salmon-red became dusky red, and the dusky 

 red, after several hours, changed to green. 



11. Solution of potash, soda, ammonia, lime, and baryta, and of carbonate of potash and 

 carbonate of soda failed to produce any colour change ; and negative results were also 

 obtained on the addition of iodic acid and starch, of hydrobromic acid and starch, and of nitric 

 acid followed by stannous chloride. 



Reactions of Solution of Strophanthidin in Water (saturated, 1 : 2000). 



1. Solution of iodide of potassium and of potassio-mercuric iodide produced a light brown 

 colour, and when this had been developed, the addition of starch solution produced the 

 usual blue reaction indicative of free iodine. 



2. When to a drop of the strophanthidin solution, placed on a white porcelain slab, a 

 drop of very dilute solution of ferric chloride was added, and then a drop of strong sulphuric 

 acid, a yellow colour was immediately produced, and, on stirring, a faint pink tinge 

 appeared, and in a few seconds the mixture became almost colourless. 



Negative results were obtained on the addition of solutions of chloride of gold, nitrate 

 of silver, platinic chloride, cobaltous chloride, acetate and subacetate of lead, mercuric chloride, 

 cupric sulphate, tannic acid, picric acid, ferric chloride, metatungstate of sodium, hydrobromic acid, 

 bromide of potassium, tribromide of potassium and Nessler's reagent. 



VOL. XXXVII. PART I. (NO. 1). B 



