1012 DR THOMAS R. FRASER ON STROPHANTHUS HISPIDUS. 



and 120° F., the green colour first produced soon became dark olive, changing to very 

 dark brown, with green at the parts which had dried, then to violet and dark violet-blue, 

 aud, finally, to black with a violet tint. 



2. With 10 per cent, sulphuric acid a nearly colourless solution was produced, which 

 remained unchanged in appearance for several hours. 



When heated between 110° and 120° F. with 10 per cent, sulphuric acid, it soon 

 became light green, grass green, dark green, deep bluish-green, deep greenish-violet, 

 very dark violet, and in about two hours, black with a violet tint. When allowed to 

 cool, the last colour remained for more than twelve hours. 



These colour changes were quite distinctly obtained with even the j^, of a grain of 

 strophanthin. 



3. Strong nitric acid, in the cold, produced a pale brown solution. 



4. Dilute nitric acid (10 per cent.) merely dissolved strophanthin, without obvious 

 change of colour. 



When heated between 115° and 130° F. with 10 per cent, nitric acid, a violet colour 

 was first developed, in which blue streaks appeared; the whole then became violet for a 

 few minutes, then yellow appeared at the margins, the violet gave place to yellowish- 

 brown, and, finally, in about forty minutes, the whole became gamboge-yellow, and 

 remained this colour for several hours. 



5. Strong hydrochloric acid dissolved strophanthin, forming a pale j^ellow solution, 

 which afterwards became brownish-yellow. 



6. Dilute hydrochloric acid (10 per cent.) dissolved it, and produced a colourless 

 solution. 



When heated between 115° and 130° F., changes were very slowly produced; in 

 about twenty minutes, a yellow colour appeared, which, however, soon passed into green, 

 and then into blue (Turnbull's), and the last colour remained for several hours. 



7. Strong sulphuric acid and bichromate of potassium, in the cold, produced successively 

 green, orange-brown, dark brown with green at the edges, and emerald-green. When 

 now heated to between 115° and 120°, the green slowly became bluish-violet. 



8. When to a minute particle of strophanthin there was added a small drop of 

 distilled water and also of dilute solution of ferric chloride, and then a drop of strong 

 sulphuric acid, a deep yellow colour appeared, which changed to pink. On mixing the 

 whole with a glass rod the pink disappeared. 



9. Solution of phospho-molybdic acid developed rather slowly a green tint, which on 

 prolonged exposure became a pure blue of considerable intensity. If an alkali was 

 added along with or after the phospho-molybdic acid, the blue colour was immediately 

 developed. 



10. Solution of potash, soda, and ammonia, and of other alkalies and their carbonates, 

 produced a faint yellow colour, which disappeared on the addition of acids. 



11. Negative results were obtained on the addition of iodic acid and starch, nitrate of 

 silver, sulphate of zinc, sulphate of copper, and Nessler's reagent. 



