1008 DR THOMAS R. FRASER ON STROPHANTHUS HISPIDUS. 



so gradually into each other that accurate determinations by this method are extremely 

 difficult. 



Exact estimations of the quantity of strophanthidin produced in the experiments were 

 not attempted. If unattached to the vessel in which the decomposition had been effected, 

 the strophanthidin crystals were collected as carefully as possible by filtration, and if 

 they adhered to the vessel they were removed by scraping ; but as the crystals are some- 

 what soluble in water, while the quantity of water used in the experiments varied 

 considerably, some loss, which was not the same in each experiment, undoubtedly occurred. 



In fact, the object of the experiments was to determine the qualitative rather than 

 the quantitative changes produced in the extract by the influence of acids, and above all 

 to demonstrate clearly that glucose and strophanthidin are produced, and that the latter 

 substance can with great facility be obtained in a crystalline form. 



A summary of the experiments is given in Table X., p. 1007. 



It has thus been shown (a) that the extract contains a glucoside, which is readily de- 

 composed by weak solutions of acids so as to produce glucose, and the crystalline body, 

 strophanthidin; (b) that glucose is produced in the extract by sulphuric, hydrochloric, nitric, 

 phosphoric, acetic, and oxalic acids, both in the cold and at an elevated temperature, but 

 by two per cent, hydrocyanic acid only at an elevated temperature ; (c) that crystalline 

 strophanthidin is produced in the cold by sulphuric, nitric, and phosphoric acids, but as 

 only very weak solutions of hydrochloric acid were used, it cannot be stated that this acid 

 is unable in the cold also to produce crystalline strophanthidin ; and (d) that crystalline 

 strophanthidin is produced at an elevated temperature by sulphuric, hydrochloric, nitric, 

 phosphoric, acetic, and oxalic acids. 



It may be added that while carbonic acid fails to decompose the glucoside, it is decom- 

 posed with the formation of crystalline strophanthidin and of glucose, by sulphuretted 

 hydrogen. 



The crystalline form assumed by strophanthidin was found to vary considerably. 

 When produced in the cold, the strophanthidin was usually in the form of rosettes or 

 nodules, consisting of lancet-shaped crystals (see Plate VII. fig. 10); but in the experiments 

 where an elevated temperature was employed, beautiful, long and slender acicular 

 needles, perfect minute prisms, and prisms grouped in stellar arrangements were also 

 produced. In the experiments at an elevated temperature with sulphuric acid, a brown 

 amorphous substance, and no crystalline strophanthidin, appeared when the acid was of 

 greater strength than 0*4 per cent.; but in the cold, even 2 per cent, sulphuric acid caused 

 the formation of crystalline strophanthidin. 



Strophanthin. 



Preparation. — The well-defined crystals produced during the evaporation of non- 

 acidulated watery solutions of the extract (pp. 996 and 997) consist, no doubt, of the 

 active principle, strophanthin. 



