23 



CHEMICAL COMPOSITION. 



We have no entire analysis of any part of the dahlia, 

 but chemists have ascertained that its tubers contain 

 a large proportion of a peculiar feculous substance, to 

 which the name of Dahline or Inuline has been given. 

 It chiefly differs from starch in one property, viz., that 

 the latter is rendered blue when treated with iodine, 

 whereas iodine imparts to dahline a yellow colour. 



Dahline is found in the roots of many other plants, 

 such as those of the Jerusalem Artichoke (Helianthas 

 tuberosus), Pellitory of Spain (Anthemis pyrethrum), 

 Meadow Saffron (Colchicam autumnale), Succory 

 (Cichorium intybus), Dandelion (Leontodon tarax- 

 acum), Angelica {Angelica archangelica), Elecampane 

 (Corvisartia (Inula) helenium), and Datisca canna- 

 bina.* 



When the roots of any of the above plants are 

 rasped, subjected to pressure, boiled in water, the infu- 

 sion filtered through linen while hot, boiled until a 

 pellicle forms on the surface, and then left to cool, a 

 white powder precipitates. This is dahline, and only 

 requires to be collected on a filter, well washed and 

 dried. One hundred parts of the roots of the dahlia 



* Chemists, considering that they had discovered in each case 

 a new principle, have called dalhine by other names, as Inuline, 

 or Helenine, when found in Inula helenium ; Alantine, when 

 from the Angelica ; and Datiscine, when from the Datisca. 



