DR THOMAS R. FRASER ON STROPHANTHUS HISPIDUS. 



999 



The first percolate of 10 of spirit to 1 of seeds, therefore, yielded 7*9 per cent, of the 

 8 "94 per cent, of total alcohol extract; and this 7 '9 per cent, contained a much larger 

 percentage of strophanthin than either of the subsequent percolates. 



Analysis No. 11. 



Alcohol Extract of Analysis No. 3 (p. 994). — 500 grains of seeds yielded 54*93 

 grains, or 10*98 per cent., of alcohol extract — 



Impure strophanthin, 36-516 grains, . 



Mucilage, 7 "46 grains, 



Resin, 7 -14 grains, .... 



= 66*479 per cent, of alcohol extract. 

 = 13-6 

 = 13-01 



93089 



The seeds had been extracted by three successive percolations with rectified spirit. 

 In the first and second percolations, 4 of spirit to 1 of seeds was used, and in the 

 third 10 of spirit to 1 of seeds. The total alcohol extract of each percolate, and the 

 quantity of strophanthin, mucilage, and resin in it are stated below. 



Analysis No. 12. 



Impure strophanthin, 



Mucilage, 



Resin, . 



1st Percolate, 4:1. 



Total Alcohol Extract, 



42-43 grains = 8 -486 



per cent, of Seeds. 



78-34 



(33-236 grains) 



3-37 



(1*42 grain) 



12-39 



(4 - 9 grains) 



2nd Percolate, 4 : 1. 

 Total Alcohol Extract, 

 5'1 grains = 1-02 

 per cent, of Seeds. 



31-568 



(1'61 grain) 



48-647 

 (2-48 grains) 



12-549 

 (0'64 grain) 



3rd Percolate, 10 : 1. 



Total Alcohol Extract, 



7 "4 grain8 = l - 48 



per cent, of Seeds. 



22-567 

 (1-67 grain) 



48-4 

 (3 '56 grains) 



21-621 

 (1-6 grain) 



per cent, of extract. 



Of the 10*98 per cent, of alcoholic extract, 8*48 per cent, was, therefore, obtained by 

 the first four ounces of percolate, and only 2*5 per cent, by the subsequent fourteen 

 ounces. The extract from the first percolate was also much richer in active principle 

 than the extract from subsequent percolates. 



It appears from the above analyses that, by the process of percolation, nearly all the 

 active principle is extracted by the first small quantity of spirit, and that this percolate 

 yields an extract consisting chiefly of active principle. Further percolates contain only 

 small quantities of the active principle, even although they may be of decidedly bitter taste ; 

 but they contain much mucilage, resin, and other undetermined substances. It is also 

 to be noted that the extract obtained from the first percolate with a moderate quantity of 

 rectified spirit differs from the extracts obtained from further percolates, not only in chemical 

 composition, but also in physical characters. After having been dried by spontaneous 

 evaporation and by exposure in vacuo over sulphuric acid, both extracts may be opaque, 

 brittle, and only slightly coloured, although the extract from the first percolate is less 

 coloured than those from subsequent percolates ; but while the former retains for an 

 indefinite time the appearance and physical characters it had acquired on becoming dry, 



