MUNJISTINE 373 



'I have likewise succeeded in extracting munjistine directly from munjeet by 

 boiling ifc with water, filtering the solution, which has a dark brownish colour, and 

 then acidulating with hydrochloric acid. The precipitate which falls is collected on 

 a filter, washed, dried, and treated with boiling spirits of wine, which leaves a large 

 quantity of pectine undissolved. 



'The munjistine which dissolves in the alcohol is obtained in a pure state by 

 repeated crystallisations in the way already indicated. The first process which I 

 have described is, however, by far the best. The colouring-matter of munjeet can 

 likewise be extracted with boiling solutions of alum ; but I find sulphate of alumina 

 greatly preferable, as the alum by its tendency to crystallise very much impedes the 

 filtration of the liquids. I likewise attempted to employ Professor C. Hopp's process 

 with sulphurous acid, which gives such excellent results with ordinary madder, but I 

 found it wholly inapplicable to munjeet. 



' Munjistine, prepared by the processes described, when crystallised out of alcohol, 

 forms golden-yellow plates of great brilliancy. It is but moderately soluble in cold, 

 but dissolves pretty readily in boiling water, forming a bright yellow solution, from 

 which it is deposited in flocks when the liquid cools. Saturated solutions almost 

 gelatinise. It dissolves to some extent in cold, but more readily in boiling, spirit 

 of wine, and is not precipitated by the addition of water. It dissolves in carbonate 

 of soda with a bright red colour. In ammonia it forms a red solution with a slight 

 tinge of brown caustic soda, producing with it a rich crimson colour. Both its 

 aqueous and alcoholic solutions, when boiled with alumina, form beautiful flakes of a 

 bright orange colour, almost the whole of the munjistine being withdrawn from 

 solution. The flakes are soluble in a large excess of caustic soda, with a fine 

 crimson colour. Munjistino dyes cloth mordanted with alumina a bright orange. 

 With iron mordant it yields a brownish-purple colour, and with Turkey-red mordant 

 a, pleasing deep orange. These colours are moderately permanent, and bear the 

 application of bran and soap tolerably well. The munjistine sensibly modifies the 

 colours produced by munjeet, giving the reds a shade of scarlet, as has been long 

 observed. 



' Commercial nitric acid dissolves munjistine with a yellow colour, but does not 

 appear to decompose it even on boiling. Fuming nitric acid (1'5) dissolves 

 munjistine in the cold, and on application of heat decomposes it, no oxalic acid being 

 produced. It readily dissolved in cold sulphuric acid with a bright orange colour ; 

 and the solution may be heated nearly to boiling without blackening or giving off 

 sulphuric acid ; it is reprecipitated by water in yellow flocks apparently unaltered. 

 When bromine water is added to a strong aqueous solution of munjistine, a pale- 

 coloured flocculent precipitate is immediately produced ; this, when collected on a 

 filter, washed and dissolved in hot spirit, furnishes minute tufts of crystals, evidently 

 a substitution-product. I may remark in passing, that when alizarine is treated with 

 bromine water in a similar way, it also forms a substitution-product, crystallising in 

 needles. 



' Munjistine, in some of its properties, bears considerable resemblance to Kunge's 

 madder orange, the rubiacine of Dr. Schunck ; it is, however, essentially different from 

 rubiacine in several of its properties, such as its solubility in water and alcohol, &c., 

 and in the amount of its carbon rubiacine, according to Dr. Schunck's analysis, con- 

 taining 67'01 per cent, of that element, while munjistine contains only 64. The 

 spectra afforded by solution of the two substances, as may be seen from the following 

 extract from a letter received from Professor Stokes, are decidedly different : 



' " The two substances are perfectly distinguished by the very different colour of 

 their solution in carbonate of soda, when a small quantity only of substance is used. 

 The solution of munjistine is red, inclining to pinkish orange, that of rubiacine a 

 claret-red. The tints are totally different, and indicate a different mode of 

 absorption. Both present a single minimum in the spectrum, but while that of 

 rubiacine extends from about D to F, that of munjistine extends from a good way 

 beyond D to some good way beyond F. The beginning and end of the band in each 

 case are not very definite, and vary of course with the strength of the solution ; there 

 can be no doubt of the radical difference in the position of the band of absorption. 

 In this way it is easy to convince oneself that the difference of the colour is not to 

 be erplained by the possible admixture of some small impurity present in one or 

 other of the specimens. With caustic potash, munjistine gives as nearly as possible 

 the same colour as rubiacine, agreeing with tho colour of rubiacino in carbonate of 

 soda. There appears to bo a slight difference in the spectrum of the munjistine and 

 rubiacine solutions, but not enough to rely on ; so that the substances are not to be 

 distinguished by their solutions in caustic alkalis. 



' A second perfectly valid distinction is, however, afforded by tho different colour 

 of the fluorescent light of the ethereal solutions. The solid substances themselves 



