ALKANET-ROOT. 375 



several articles in domestic economy. The Dutch 

 buy up large quantities, which are used by them to 

 colour wines and the rinds of cheese*. 



When infused with distilled water they afford an 

 excellent test. Litmus, well known to chemists as 

 a test for detecting alkalis or acids, is prepared from 

 this plant. The former changes its colour to blue, 

 the latter to red. Persons who formerly prepared 

 the litmus purposely concealed the source whence it 

 was derived, pretending that it was extracted from 

 the hdiotropium tricoccum, in order to mislead 

 others and restrict the preparation to themselves. It 

 is now, however, well known that croton is the plant 

 from which litmus is obtained. 



Alkanet-root is another colouring drug, which is 

 not very much used as a dye. It is the root of a 

 kind of bugloss, or anchusa tincloria, a native of the 

 Levant, and the warmer parts of Europe. France, 

 particularly about Montpelier, produces it in the 

 greatest abundance. Our chief supplies are drawn 

 thence ; for though it is raised in England, the 

 roots are much inferior to those of foreign growth. 

 It is a hardy plant, growing with a branchy stem, 

 having oval leaves set alternately on the branches. 

 The flowers come forth from the summit in long 

 spikes, growing grouped together like the tiles of a 

 house. It is propagated by seed, sown in beds in 

 either spring or autumn; when sufficiently advanced 

 the young plants are transplanted at intervals of two 

 feet from each other. The colouring matter is con- 

 fined to the bark of the roots, and therefore the small 

 roots, having more bark in proportion to their bulk 

 than the large ones, afford the most colour, and are 

 considered the best. 



Alkanet-root is insoluble in water an aqueous 

 * Beckmann. 



