Dr Hope on the Camellia Japonica, Sfc. 193 



Monday/, 3d April 1843. 



Sir T. MAKDOUGALL BRISBANE, Bart., President, 

 in the Chair. 



The following Communications were read : — 

 1. Chemical Observations on the Flowers of the Camellia Ja- 

 ponica, Magnolia Grandiflora, and Chrysanthemum Leu- 

 canthemum, and on three Proximate Principles which 

 they contain. By Dr Hope. 



The author first called the attention of the meeting to the prin- 

 cipal facts which he had established in the two memoirs read to the 

 Society in the year 1836. 1^^, Of these the most important are, 

 that when the acids cause a red colour, and alkalis a green or yel- 

 low, in a blue vegetable infusion, they act on different substances ; 

 — the acids on erythrogen, and the alkalis on xanthog§n. 2<iZy, 

 That the compound of alkalis and xanthogen is of a yellow colour, 

 and that when a blue infusion is changed to green, it is owing to 

 the gradual intermixture of the newly generated yellow with the 

 original blue. 



Camellia Japonica. — The blossoms of the beautiful double white 

 Camellia Japonica are remarkable for the peculiar matters which 

 they contain, two of which appear to be distinct vegetable prin- 

 ciples. When a parcel of the petals is infused in boiling-hot water, 

 and digested for some time, a nearly colourless infusion is obtained, 

 which is not visibly affected by acids. When solution of potash is 

 added, a light orange colour appears, w^hicli gradually deepens, till 

 in a few hours it acquires a very deep orange hue. Solution of 

 ammonia causes a similar effect. When lime-water is employed, it 

 produces turbidity in the infusion, and a pinkish -red colour. This 

 colour gradually assumes a richer tint, and in about 24 hours ex- 

 hibits a deep pinkish-red. The author has applied the same alkal- 

 escent agents to above 150 flowers, both white and coloured, with- 

 out observing any similar effect. 



To this colourable matter he gives the name of Camelline. The 

 author tried the effects of various reagents, but no interesting facts 

 resulted. 



When any portion of the flower-leaf is bruised, whether remain- 

 ing on the parent plant or removed from it, it immediately begins 

 to assume a rusty or ochry tint, which grows deeper and deeper, 

 till it arrives at the tint of perfect ochre. 



By various experiments, it was proved that this change of colour 



VOL. XXXVI. NO. LXXI. JANUARY 1B44. N 



