1887 .] Professor Fraser on Chemistry of Strophanthin. 373 
iodide of potassium, nor by many other reagents ; except that nearly 
all acid reagents cause the solution to become slightly hazy, and it 
is then found that the solution contains glucose. This decom- 
position is also produced by sulphuretted hydrogen, and for this 
reason it is not advisable to use sulphuretted hydrogen in any pro- 
cess for preparing strophanthin. 
Indeed, all the mineral acids, excepting carbonic acid and many 
of the organic acids, resolve strophanthin, even in the cold, into 
glucose and a substance which I have named strophanthidin. A 
very pretty crystallisation of the latter is spontaneously produced, 
in a few hours, in a solution of strophanthin in 1*5 per cent, 
sulphuric acid. Contact at the ordinary temperature for even 
three days with dilute sulphuric acid does not apparently entirely 
decompose the strophanthin, as an additional quantity of glucose 
seems to be afterwards produced when the solution, filtered from 
strophanthidin, is heated at 212° F. for a few hours. Thus, when 
strophanthin was decomposed at the ordinary temperature by contact 
for about three days with 1 *5 per cent, sulphuric acid, there was 
obtained 3 7 ’5 per cent, of crystalline strophanthidin, and about 20 
per cent, of glucose.* The crystals of strophanthidin having been 
removed by filtration, and the almost colourless, bitter, and acid 
fluid having been boiled for four hours, it was now found that the 
glucose had increased to 26*64 per cent., and that about 4*3 per 
cent, of an amorphous brownish substance had been formed. 
This action of acids renders it apparent that an acid, and especially 
a mineral acid, should not be used in the preparation of strophanthin. 
Thus, in 1877, seven years after the publication of my first com- 
munications on this subject, Hardy and Gallois described a process 
in which, by using for the extraction of the seeds rectified spirit 
acidulated with hydrocholic acid, they obtained a crystalline pro- 
duct which they believed to be strophanthin. There can be little 
doubt, however, that their crystalline product was strophanthidin, 
not only because the process they employed would decompose the 
strophanthin into strophanthidin and glucose, but also because 
* In the solution obtained by this decomposition, the exact estimation of 
glucose by Fehling’s solution is rendered difficult and uncertain by a green 
colour being produced, which persists after the blue colour of Fehling’s solu- 
tion has disappeared. 
