421 



tints of the Camellia are in no way dependent on, or connected with, 

 the iron which it contains. 



Magnolia Grandijlora. — When the petals of the Magnolia 

 Crrandifiora aro boiled for sonic time in distilled water, a liquor of 

 a very light yellowish brown Is obtained. This colour Is banished 

 by sulphuric acid. Solution of potassa immediately causes a deep gall- 

 stone yellow, shewing that this, like other white flowers, contains no 

 erythrogen, but abounds in xanthogen. That matter, which becomes 

 of an ochry hue by the contact of air, is very abundant In the Mag- 

 nolia, so that, if the cuticle be scraped off, in less than a minute the 

 place of abrasion exhibits the ochry tint. The petals of the snow- 

 white Magnolia conspicua exhibit the same phenomena in a stiU 

 more remarkable degree. If a petal of this beautiful flower be 

 bruised between the fingers and thumb it immediately becomes of a 

 very deep brown, and ere long almost black. Some other white 

 flowers, by being crushed and exposed to the air, also acquire the 

 ochry tint, but in a much inferior degree to those already men- 

 tioned. The ochry-growing matter is not confined to white flowers. 

 It exists in difi^erent species of the blue flowers of the Aconitum, par- 

 ticularly the napellus. 



The third flower of which Dr Hope gave an account, was the 

 Chrysanthemum leucanthemum, the ox-eye daisy. A sti'ong decoc- 

 tion of the white petals exhibits a light brown colour, which potash 

 quickly converts into the usual gallstone yellow. "VMien sulphuric 

 acid is dropped into this decoction, the colour becomes a light prim- 

 rose yellow, and the liquid immediately assumes a gelatinous state. 

 This jelly gradually becomes more consistent, and, In about a quar- 

 ter of an hour. It Is so firm that the capsule containing it may be in- 

 verted without the jelly falling out. The matter thus gelatinized by 

 sulphuric acid is peculiar to this plant. The author has applied sul- 

 phuric acid to the infusion of at least 150 flowers, without any simi- 

 lar result taking place. The author conceives that the gelatinising 

 matter is a distinct vegetable principle, to which he gave the name 

 of Leucanthemine. To support this view, he drew a comparison be- 

 tween it and the coagulable matters both of the animal and vege- 

 table kingdoms, viz. animal albumen, casein, fibrin, and vegetable al- 

 bumen. In drawing this comparison, the author described some re- 

 markable properties of tliese albuminous matters, which have escaped 

 the observation of all the investigators of the chemistry of organic 

 substances, and some of which he had been in the habit of exhibiting 

 in his lectures for nearly half a century. These are, principally, that 



