VEGETABLE DYES 115 
the mordanted parts only. With well-chosen com- 
binations quite pleasing effects can be obtained in this 
way. 
Artificial alizarin has now entirely superseded madder 
for Manchester cotton printing; the colours it gives 
are brighter though not quite so fast as those from natural 
madder. Also a number of derived alizarins have been 
prepared with similar properties, and some of these 
complete the colour range by providing colours from 
the blue end of the spectrum. 
Besides these three groups, which include the chief 
textile dyes of the past, there are a few plant dyes of 
limited applicability which, like the insect dye, cochi- 
neal, have held their own and will probably continue 
to do so, because of their harmlessness. One of the 
chief of these is alkanet, much used for colouring medi- 
cines, pomades, sweets, etc. The real alkanet of the 
East is obtained from the roots of Lawsonia alba; in 
this country “‘ false ’’ alkanet only is used, made from 
the roots of Anchusa tinctoria, a plant cultivated on a 
small scale for the purpose. Alkanet gives violet or grey 
shades with iron or alum mordants, 
These, then, are the most important vegetable dyes. 
Every one of them has played a worthy part in the 
history of industrial development, and two at least, 
indigo and alizarin, have pointed the way to science 
in the development of new colour principles. But it 
is more important, for present-day practice, to know 
how they stand in relation to modern synthetic dyes. 
There are always enthusiasts to be found who will up- 
hold anything ancient, and who would have us believe 
that the road to the millennium leads through the past. 
