IN THK MOTOR OEGA.NS OF LEAVES. 



23 



permanent pale, dull, brownish pink tint. The flower waa now transferred to a 

 carbonic acid chamber in which the petals gradually reddened, and in the course of 

 twenty-four hours tiny had regained a vivid scarlet colour. 



Experiment II. — Petal* of the same Erythrina, when immersed in ab>-»luto alcohol, 

 were at once bleached to a very pale pink, the alcohol at the same lime acquiring 

 a very pale, reddish topaz tint, which rapidly reddened in a carbonic acid chamber 

 and became vivid scarlet on the addition of a i» w drops of glacial acetic acid. 

 Alternate additions of solutions of caustic potash and glacial acetic add to alcoholic 

 extract which has become scarlet owing to prolonged exposure in a carbonic acid 

 chamber, secure alternating discharge and reformation of the colour. 



Experiment III. — A flower of a scarlet variety of Hibiscus rosa-stnensis was set in a 

 chloroform- chamber. The colour very rapidly began to become dulled, and within an 

 hour w r as of a dull maroon red, the corolla at the same time showing the initial Mage 

 of collapse. The chloroform was now removed from the chamber and a vessel «-f 

 glacial acetic acid substituted for it. Collapse of the corolla continued to advance 

 steadily to completion, but at the same time its colour gradually revived and ultimately 

 became once more vivid scarlet. 



Experiment IV. — A similar flower of Hibiscus, momentarily immersed in boiling 

 water, collapsed at once, the colour at the same time becoming purplish. The water 

 also acquired a purplish hue, due to extraction of pigment and partial bleaching of 

 the corolla. The purplish infusion was rendered bright red 'by the addition of 



acids. 



Experiment V. — A similar flower placed in a chloroform chamber gradually unuVr- 

 went the same changes as that in Experiment III. 



When the colour had become of a deep maroon red, the chloroform was removed 

 and a vessel of fuming nitric acid substituted for it. Restoration of the colour began 

 visibly almost at once, and a vivid scarlet was gradually re-established. 



Experiment VI. — A similar flower was enclosed in a metal box and buried in a 

 mixture of ice and salt. After an hour and a half of exposure it was found to be 

 stiffly frozen and of a dull red colour. It was now placed in a simple hermetically 

 closed chamber, and the colour soon passed on to the same deep maroon tint 

 which is developed under exposure to chloroform, flaccidity and collapse also advancing 

 rapidly. On the following day it was quite flaccid and deep maroon. A vessel of 

 o-lacial acetic acid was now introduced into the chamber, and twenty-four hours later 

 the corolla was once more vivid scarlet. 



Experiment VII. — Petals of scarlet Hibiscus immersed in absolute alcohol became at 

 once deep purple and yielded a neutral extract of a reddish topaz colour. Treated 

 with acids, this extract became vivid red; and with alkalis dull green, passing on to 

 orange yellow. 



Experiment VIII. — A scarlet Hibiscus flower was set in a moist ammonia-chamber. 

 Purplish black spotting of the corolla began to appear within a minute and extended 

 rapidly. As the blackening extended inwards from the periphery to the centre of the 



