PLANT ANALYSIS AS AN APPLIED SCIENCE 205 



solubility of indigo in sulphuric acid is utilized for blue dyeing 

 of wools. 



Indigo has been made artificially by several methods, though 

 the process so far is too expensive to allow the manufactured 

 compound to replace the commercial supply from plants. 



The table of statistics is as follows : 



Amount of indigo l imported : Pounds. Value. 



1884 2,674,062 $2,267,048.00 



1885 3,035,934 2,007,066.00 



Artificial indigo : Pounds. Value. 



1884 None. 



1885 3,300 $3,600.00 



The dye commonly known as logwood has been cultivated 

 in Jamaica 2 since 1715, and has been known and used in 

 Europe from a short period after the discovery of America. 

 The commercial supply of the dye is from Hamatoocylin 

 campechianum, a tree belonging to the natural order Legumi- 

 nosce. It is the wood of the tree which is used, and is met in 

 commerce in the shape of large, irregular blocks. 



The only other tree besides logwood in which haematoxylin 

 so far has been discovered is the Saraca indica, of the same 

 natural order. 



I stated 3 before the Academy of Natural Sciences, in Nov- 

 ember, the discovery of this principle in my analysis of the 

 bark of the Saraca indica. 



The Saraca indica 4 is called in India the asok or asoka 

 tree, and it is said when this tree is in full blossom, there is 

 nothing in the vegetable kingdom which affords a more beauti- 

 ful sight. Frequent mention is made of the plant in Hindoo 

 mythology, and the bark is much used by native physicians 

 in some diseases. 



1 Bureau of Statistics, 1885. 2 Crookes, p. 342. 



3 "On Haematoxylin in the Bark of Saraca Indica," by Helen C. De S. 

 Abbott. Proc. Acad. Nat. Sciences, Philadelphia, November 30, 1886. See 

 p. 171. 



4 The Materia Medi-ca of the Hindus, by Udoy Chaud Dutt. Calcutta, 

 1877. 



