220 MALAY POISONS AND CHABM CUBES 



glucosidal resin containing no sulphur ; he found it was 

 chiefly contained in the bark of the root, and gives the 

 yield from a whole root as 2-5 to 3 per cent. L. Wray, 

 jun., who extracted it independently (1892), called it 

 " tubaine," being unaware of Greshoffs discovery. 

 Wray found that one part of his " tubaine " in 350,000 

 parts of water quicldy proved fatal to fish, and that 

 water containing a millionth part of " tubaine " killed 

 fish in fifteen to thirty minutes, according to species 

 (Ref . 24) . Greshoff found that a much smaller quantity 

 of his derrid " would kill fish : " a solution containing 

 only one five-millionth part stupefied goldfish and killed 

 them within half an hour,*' Van Sillevoldt investigated 

 the chemistiy of Greshoff*s active principle about the 

 time of its discovery (Eef. 16). In 1902 Power investi- 

 gated the properties of D. uliginosa (Ref. 16). More 

 recently tlio poisonous properties of D. elliptica have 

 been reported upon by van Hasselt (1911) and by 

 A. Campbell (1916). The work of H. E. Durham has not 

 hitherto been published and is privately communicated. 



According to Greshofi', crude " derrid" exists in the 

 root together with a brown colouring matter called 

 *' derris red," a brown mahogany-coloured body possibly 

 derived from the tannin of the plant* Derris-red " is 

 non -toxic and can be removed by treating the coarsely 

 powdered root-bark in a percolator with water at high 

 or ordinary temperatures. Dmham found that the 

 very active constituent is in two forms, crystalline and 

 resinoid ; both of these are highly toxic, but the resin 

 is more active : dilutions of one part in fom* or five 

 millions of water will kill tadpoles within twenty-four 

 hom-s, but in dilutions fom- or five times such strength 

 only tlu*ee or fom* hours elapse before death. Gudgeon 

 exposed for four hours in two-million-fold dilution of the 

 crystals did not recover in fresh water ; one in 



