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The Way Out For Indian Planters. 



How is the German move to be met ? There is a way out. It 

 will be found in improved cultivation, on scientific principles, of 

 the plant, and in improved methods of extracting the natural dye 

 from the indigo plant. Considerable initiative and some outlay of 

 capital is required. The old mechanical method of hand-and-foot 

 labour, as handed down from generation to generation, without any 

 thought of improvement, will have to go. The process of extract- 

 ing the maximum quantity of pure indigotine from the vats is being 

 closely inquired into by experts, I am told. Authorities in che- 

 mistry will undoubtedly succeed in obtaining increased proportions 

 of colouring matter from the plant, which has hitherto not been 

 expected to give more than i-i lbs. of indigo for loo lbs. of the 

 plant. At the present moment experiments are in progress in Cam- 

 bodia, which will be of particular interest to indigo planters in 

 British India. I am told that one Martinique planter has succeeded 

 in obtaining a product containing .73 per cent, of pure indigotine 

 at a cost of is. id, per lb. This is at a notably lower cost than 

 that of artificial indigo, as stated above. 



It is thus far from a certainty that natural indigo will disappear 

 from the market as soon as madder did when threatened by German 

 chemical competition. Indigo planters willing to radically alter 

 their old-time methods, improve their cultivation of the crops and 

 alter the mode of extraction of the dye, and who, by means of com- 

 bination with official help, can, make the necessary sacrifice that 

 the changes will entail may take heart of grace. The last word 

 has not been said yet on the subject of natural indigo. 



Dr. Calmette's Method of Extraction. 



Dr. CALMETTE, of Lille, has patented the following process for 

 the extraction of indigotine from the plant. Hitherto the leaves of 

 the indigo plant have been placed in masonry vats in layers. The 

 vats are then filled to two-thirds with water, care being taken not 

 to crush the leaves. The leaves are held down by planks, and 

 water is let in to cover them. Fermentation then sets in and the 

 liquid, first yellow, becomes by degress green. The temperature 

 of the vat rises, and soon the surface of the vat is covered by a film 

 having a metalic scheen. In this operation "indican," the sub- 

 stance contained in the plant, transforms itself into glucose and 

 white indigo under the influence of the fermentation caused by a 

 bacillus living on the leaf of the indigo plant. The white indigo is 

 transformed into blue indigo by simply beating up the liquid bring- 

 ing it into contact with air. 



A deposit of indigo flakes is formed at the bottom of the v ats. 

 It is boiled up with water, dried, and made into small cakes. The 

 primitive method gave only about a third of the indigo contained 

 in the plant. There is a considerable loss owing to the fermenta- 

 tion. Dr. CALMETTE has endeavoured to regulate this fermentation ; 

 he suppresses it entirely and treats the leaf in close vats at a tem- 

 perature of fifty to sixty degress centigrade, unexposed to the 

 oxygen of the air. The extraction of the " indican " and its trans- 



