368 



Prof. H. E. Armstrong and others. [Apr. 3. 



amygdalin from the leaf is therefore all the more remarkable in view of 

 their presence in the seed. 



Most of the varieties of Prunus we have been able to test afford hydrogen 

 cyanide but the amount procurable from the leaf is often very small and is 

 subject apparently to great variation throughout the season. At times it is 

 scarcely detectable in leaves of the bitter almond and these often contain 

 less than do those of the sweet variety growing alongside them. In the case 

 of the fruit, cyanide is present during the earlier stages even in the sweet 

 almond but disappears as it ripens. 



We have never obtained more than minute amounts of hydrogen cyanide 

 from leaves of Zaurus lusitanica and have often failed to detect any ; it is 

 present in minute proportion in the flower and usually in young leaves 

 formed at the flowering period and soon afterwards. The leaf is intensely 

 bitter ; this fact, taken together with the high activity towards salicin is 

 probably an indication of the presence of a glucoside other than prunasin. 



We were fortunate in securing a considerable quantity of the ripe fruit 

 last autumn and from this were able to separate amygdalin without 

 difficulty merely by extraction with boiling alcohol. 



On analysing the seed kernels, they were found to contain : oil, 9 per cent, 

 (iodine number, 90 - 4); protein, 26"9 per cent.; moisture, 4 - l per cent.; ash, 

 2-8 per cent. 



The Aucuba japonica leaf is rich in enzyme and judging from the variation 

 in the values obtained with prunasin and salicin it is possible that more than 

 one is present. The absence of amygdalin from the seeds, coupled with the 

 fact that these contain a large percentage of the glucoside aucubin, is 

 confirmation of our view that the formation of amygdalin in the Prunus fruit 

 is consequent on the presence of amygdalase. The two species of Garrya 

 examined are allied to Aucuba but less rich in glucoside (aucubin) ; it will 

 be noticed that they also contain less enzyme. 



The variations in activity towards salicin shown by the several specimens 

 of Epilobium angustifolium we have examined are remarkable. That 

 of Swiss origin was picked in the Saas valley in August 1910 and we 

 were specially attracted by its sturdy growth and willow-like character ; this 

 in fact led us to test its action on salicin. Two separate specimens from the 

 Midlands obtained in the following September were far less active and a 

 specimen picked in an Ayrshire garden at Whitsuntide, 1911, was similar 

 to these. The specimens secured in August last year in three different 

 districts in Norway correspond fairly with the Swiss specimen in activity, that 

 picked at a considerable elevation in the Myrdal resembling the Swiss plant 

 most closely. 



