BY JA^r^:s .\r. i-ktijik. 459 



tie i>lants hitherto investigatefl. The lea\es of the I'dlhiwiiiu- phiiits cnutaiii the 



aiuoiints stated in )iigs. '^■'c of the dry luateriah 



HCX 



Paiiyium edule, Greshoti 11(10 uig-s. ^^ 



Taraktoyenos Blumei, Treiib 333 



Ileterodendroii oleaefolin, this i>a|)er 328 



Pliaseolii.s hinafus (Lima beans), Treiib 320 



Gynocurdia odoratci, Treub 220 



Indiffofera (jalegoides^ Treub 154 



Bitter abnonds (seeds), Guignard 150 



Passi flora II erbertiana (native to N.S.W.), Treub .. 143 



Hecea Brasilieiisis (Para rubber plant), Treul) .... 138 



Andropojioii sorghum, Dowell 51 



Ci/iiodo)i ineompletu^ (blue couch grass), Petrie .. 25 



Calcidation of fatal dose of Heterodendron leaves. 



The lethal aniuunt of hydrocyanic acid is usually stated as 1 nig. [ler kilo- 

 gram of body-weight. 



A man or sheen would therefore require about (JO mgs. 



This amount is obtained from about 40 bitter almonds. 



This amount is also obtained from 90 gms. of fresh gTeen leaves of Hetero- 

 dendron, which is equivalent to 3 ozs. in weight, and 230 fresh leaves of average 

 size, or to 1 oz, of air-dried leaves. 



A single leaf of Heterodendron of average size will yield 0.35 mg. of hydro- 

 cyanic acid; and 1 oz. weight of leaves which have been cut and lying in the sun 

 and air to dry, will give sufficient hydrocyanic acid to poison a sheep. Hetero- 

 dendron is therefore much more poisonous than bitter almonds; in fact, it is 

 more than twice as strong, and thirteen times more so than the blue couch gi'ass. 



SU3I1I.\RY. 



Heterodendron oleaefolia is a native Australian e\ergreen tree, the foliage of 

 which was much used for cattle-feeding during the drought. It contains a cyano- 

 genetic glucoside yielding, when hydrolysed, 0.328 % of hydrocyanic acid. It 

 is therefore one of the most poisonous cyanogenetic plants known, yielding more 

 than twice as much hydrocyanic acid as bitter almonds. One ounce of the air- 

 dried leaves forms a lethal amount for one sheep. 



The leaves are invariably found to be deficient in enzyme, and required the 

 addition of emulsin in the estimation, to bring about the comjilete decomposition 

 of the glucoside. 



