72 Dr. T. R. Fraser. Acokanthera Schimperi : [Apr. 25, 



Somaliland to prepare an arrow-poison. This glucoside, dried at 

 120 C., on combustion yielded C 48'3 per cent., H 6'5 per cent., and 

 to it the name ouaba'in was given. 



In 1888 Arnaud obtained from the wood of an unidentified species 

 of Acokanthera, provisionally named Acokanthera ouaba'io, Cathelineau 

 (Carissa ouabaw, Franchet and Poisson), used in North Somaliland 

 to prepare an arrow-poison, a crystalline glucosidal active principle, 

 which, dried at 140 C., on combustion yielded (i) C 58'14 per cent., 

 H 7 - 67 per cent., corresponding with the formula G 30 H- ie Q l2 , and 

 dried at 100 C., with the formula C 3 oH4 6 12 ,H 2 ; and to it the name 

 ouabain was also given. 



In 1893 Lewin, and also Merck, separated from the wood of another 

 Acokanthera, named Acokanthera Deflersii, Schweinfurth, an amorphous 

 glucosidal active principle, which, dried at 100 C., on combustion 

 yielded C 58'32 per cent., H 8'01 per cent. ; and which is also named 

 by Lewin ouabain, and erroneously stated to be the active principle 

 of Acokanthera Schimperi. 



The complete recognition of the species of Acokanthera i of 

 primary importance, because several supplies of the wood of uniden- 

 tified species of Acokanthera sent to us from East Equatorial 

 Africa yielded only a glucosidal active principle, which was amor- 

 phous. 



The characters of the crystalline active principle which we have 

 separated from the wood of the fully identified species Acokanthera 

 Schimperi, Benth. and Hook., agree with those of the crystalline 

 active principle separated by Arnaud from the wood of the uniden- 

 tified species of Acokanthera, provisionally named ouabalo ; and also 

 from the seeds of an unidentified species of Strophanthus, obtained 

 from West Africa. 



As, therefore, the name ouabain is used for three quite different 

 Eubstances, and is itself derived from merely a vernacular word 

 " wabayo," which is used in a restricted district, we would suggest 

 that, in accordance with a usual custom, the crystalline active 

 principle of Acokanthera Schimperi should be named acokantherin 

 and not ouabain. 



In the Preliminary Notice of this paper there was appended a note, 

 making brief mention of some of the most important general obser- 

 vations made by several investigators upon the pharmacological action 

 of those arrow-poisons which, at the time when the investigations 

 were made, were not known to be derived from the Acokanthera 

 species, and upon several non-crystalline and crystalline glucosidal 

 substances to which the arrow-poisons owe their action. In the 

 present paper the work accomplished by Arnott and by Haines in 

 1853, by Ringer in 1880, by Rochebraune and Arnaud in 1881, by 

 Laborde in 1887, by Langlois and Varigny, by Grley and Rondeau, 



