DR. EDWARD SCHUNCK ON INDIGO-BLUE. 221 



century, and at one time, particularly about the years 

 1838 to 1840, formed the subject of numerous investigations 

 by eminent French botanists and chemists, such as Turpin, 

 Joly, Baudrimont, Pelletier, Robiquet, and others, some 

 hopes being entertained that the plant might be cultivated 

 profitably in France. The numerous trials made with this 

 view having led to no result, the matter fell again into 

 oblivion, and this interesting plant remained what it was 

 before, a mere curiosity. 



I obtained the seeds of the plant from Messrs. Vilmorin, 

 Andrieux & Co., the eminent horticulturists of Paris, and 

 therefore felt sure of their genuineness. They were sown 

 in a hotbed, and germinated rapidly. As soon as the 

 young plants were a few inches high they were transplanted 

 into the open ground, where they grew vigorously, pro- 

 ducing an abundance of leaves and attaining during the 

 summer season a height of nearly three feet. Towards 

 the end of summer spikes of pretty pink flowers, resembling 

 those of other species oi Polygonum, made their appearance. 

 The seed, however, did not ripen in the open air, the plant 

 being cut down by the early frosts before this could take 

 place ; but, by growing a few plants under glass, I obtained 

 a quantity of well-matured seeds, which yielded another 

 crop in the following season. 



For a botanical description of Polygonum tinctorium I 

 must refer to Turpin'^ and Jolyf, the latter of whom has 

 given a full account of its structure and affinities. Of the 

 various organs, the leaves, being the seat of the blue co- 

 louring-matter, are alone of any interest to the chemist. 

 These leaves, which are large, oval in shape, and glossy, 

 show no indication of the presence within their tissue of 

 any pigment beside the chlorophyll to which they owe 



* Comtes Renclus, t. vii. p. S06. 



*(• ' Sur le Polygonum tinctorium : ' Moiitpellier, 1839. 



