194 



Mr. G. . Currey. 



6. Comparisons between the absorptions of the proteins of human serum 

 reveal absorption bands for the horse somewhat greater in dimensions than 

 those for the human. 



7. The optical properties of the proteins of serum have been investigated 

 with fairly satisfactory results. 



8. Processes for the separation and purification of the proteins have been 

 elaborated. 



* The Colouring Matter of Red Roses. 



By Geoffrey Currey. 



(Communicated by Prof. F. Keeble, F.E.S. Eeceived August 12, 1921.) 



An examination of the petals of the red rose " George Dickson," has shown 

 that the anthocyan pigment contained therein is the cyanidin glucoside, 

 cyanin. It is present to the extent of about 9-10 per cent, by weight of 

 the dried petals, and exists in the petals as an oxonium salt (i.e., in combina- 

 tion with a plant acid). A yellow glucoside sap-pigment also occurs in the 

 same flowers, but beyond the fact that it has been shown to be capable of 

 producing an anthocyan, by reduction, and that it is not a glucoside of the 

 flavonol myricetin, it has not been further identified, on account of the small 

 quantity present. .Further work may show it to be a glucoside of quercetin, 

 and corroborate the work of Dr. Everest,* on the purple-black viola, in which 

 it was shown that an anthocyan (" violanin ") and the flavonol glucoside from 

 which it could be produced, by reduction (a glucoside of myricetin), are 

 present, side by side, in the same flowers. This would be additional evidence 

 in favour of the hypothesis that <: anthocyans are produced, in nature, by the 

 reduction of the flavonols." It is interesting to note that this rose, grown in 

 Australia, contains the same colouring matter as was isolated by Willstatter 

 and Nolanf from the rose known as " Eosa Gallica," grown in Europe, and 

 shows how widely these colouring matters are distributed in nature. 



The rose " George Dickson " was chosen for this investigation on account of 

 its deep red colour, which would indicate a fairly large percentage of the 

 anthocyan pigment. The flowers from which the petals were gathered were 

 grown by Mr. G. Knight, at his nursery, Parramatta Eoad, Homebush, and 



* ' Koy. Soc. Proc.,' B, vol. 90, p. 255 (1918). 

 t ' Annalen,' vol. 408, p. 1 (1915). 



