ON THE CARAJURU AND CHICA. 
149 
XXXVI.— ON THE CRAJURU OR CARAJURU AND CHICA, A 
NEW RED TINCTORIAL SUBSTANCE FROM SOUTH 
AMERICA. 
By J. J. Virey. 
The leaves of various plants contain, besides the ordi- 
nary elements of vegetable organization, peculiar coloring 
principles; thus, for instance, blue leaves are frequently 
filled with indigo, as is observed in Polygonum, Isatis, 
Nerium, Pergularia, Hedysarum, Galega, &c, for even 
the cows which feed upon them sometimes give blue milk. 
Other leaves naturally become red, owing to certain pro- 
perties peculiar to their juices, but especially to the action 
of heat and light. These kinds of vegetables, generally as- 
tringent or acid, are more frequent in southern countries, 
where they develope their red tints to a greater extent at an 
advanced period of vegetation, as in autumn ; this is the 
time for obtaining peculiar red dyes. We might enumerate 
a long list from among the Rubiacex, Rosacea, Legumi- 
7iacess, &c, even of our temperate climate, but the richest 
tinctorial products are peculiar to intertropical regions. 
M. de Humboldt has. described in the 'Annales de 
Chemie et Physique,' (vol. xxvii. p. 315,) under the name 
of Chica, a vegetable product of a brick-red color, obtained 
by macerating in water the leaves of Bignonia chica, a 
shrub of the family of the Bignoniacese from equinoctial 
America. 
As we have obtained from Para in Brazil, under the de- 
nomination Crajuru or Carajuru, a substance not only 
analogous in its physical and chemical characters to the 
Chica, but of a red brown violet tint, much more beauti- 
ful or rich, and like vermillion, whilst the other appeared 
duller and much inferior, it may be useful to give fresh de- 
