144 Supposed Identity of Biliverdin with Chlorophyll, &c. [Feb. 25, The paper concludes with a brief deduction of the observed laws of Conjugate and Secondary Joints from known mechanical principles. II. "On the supposed Identity of Biliverdin with Chlorophyll, with remarks on the Constitution of Chlorophyll." By G. G. STOKES, M.A., Sec.R.S. Received February 25, 1864. I have lately been enabled to examine a specimen, prepared by Professor Harley, of the green substance obtained from the bile, which has been named biliverdin, and which was supposed by Berzelius to be identical with chlorophyll. The latter substance yields with alcohol, ether, chloroform, &c., solutions which are characterized by a peculiar and highly distinctive system of bands of absorption, and by a strong fluorescence of a blood-red colour. In solutions of biliverdin these characters are wholly wanting. There is, indeed, a vague minimum of transparency in the red; but it is totally unlike the intensely sharp absorption-band of chlorophyll, nor are the other bands of chlorophyll seen in biliverdin. In fact, no one who is in the habit of using a prism could suppose for a moment that the two were identical; for an observation which can be made in a few seconds, which requires no apparatus beyond a small prism, to be used with the naked eye, and which as a matter of course would be made by any chemist working at the subject, had the use of the prism made its way into the chemical world, is sufficient to show that chlorophyll and biliverdin are quite distinct. I may take this opportunity of mentioning that I have been for a good while engaged at intervals with an optico-chemical examination of chlorophyll. I find the chlorophyll of land-plants to be a mixture of four substances, two green and two yellow, all possessing highly distinctive optical properties. The green substances yield solutions exhibiting a strong red fluorescence; the yellow substances do not. The four substances are soluble in the same solvents, and three of them are extremely easily decomposed by acids or even acid salts, such as binoxalate of potash ; but by proper treatment each may be obtained in a state of very approximate isolation, so far at least as coloured substances are concerned. The phyllocyanine of Fremy* is mainly the product of decomposition by acids of one of the green bodies, and is naturally a substance of a nearly neutral tint, showing however extremely sharp bands of absorption in its neutral solutions, but dissolves in certain acids and acid solutions with a green or blue colour. Fremy's phylloxanthine differs according to the mode of preparation. When prepared by removing the green bodies by hydrate of alumina and a little water, it is mainly one of the yellow bodies; but when prepared by hydrochloric acid and ether, it is mainly a mixture of the same yellow body (partly, it may be, decomposed) with the product of decomposition by acids. of the second green body.. As the mode of preparation of phylloxant heine is rather hinted at than described, I can only conjecture what the substance is; but I suppose it to be a mixture of the second yellow substance with the products of decomposition of the other three bodies. Green seaweeds (Chlorospermea) agree with land-plants, except as to the relative proportion of the substances present; but in olive-coloured sea-weeds (Melanospermea) the second green substance is replaced by a third green substance, and the first yellow substance by a third yellow substance, to the presence of which the dull colour of those plants is due. The red colouringmatter of the red sea-weeds (Rhodospermea), which the plants contain in addition to chlorophyll, is altogether different in its nature from chlorophyll, as is already known, and would appear to be an albuminous substance. I hope, before long, to present to the Royal Society the details of these researches. "Continuation of an Examination of Rubia munjista, the EastIndian Madder, or Munjeet of Commerce." By JOHN STENHOUSE, LL.D., F.R.S. Received December 21, 1863 *. In the former, preliminary notice of the examination of the Rubia munjista †, the mode of extracting munjistine from munjeet, and a number of its properties, have been already described. I now proceed to detail some results which have been subsequently obtained. When munjistine is extracted from munjeet by boiling solutions of sulphate of alumina, as the whole of the colouring matter is not extracted by a single treatment with the sulphate of alumina, the operation must be repeated five or six times instead of two or three as was formerly stated. During the boiling of the munjeet with sulphate of alumina, a large quantity of furfurol is given off. I may mention, in passing, that the most abundant and economical source of furfurol is found in the preparation of garancine by boiling madder with sulphuric acid. If the wooden boilers in which garancine is usually manufactured were fitted with condensers, furfurol might be obtained in any quantity without expense. In addition to the properties of munjistine already described, I may mention that acetate of copper produces in solutions of munjistine a brown precipitate but very slightly soluble in acetic acid. 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 alcohol, furnishes minute tufts of crystals, evidently a substitution-product. Unfortunately these crystals are contaminated by a resinous matter, from which I have been unable to free them, and therefore to determine their composition. When munjistine is strongly heated on platinum foil, it readily inflames and leaves no residue; when it is carefully heated in a tube, it fuses, and crystallizes again on cooling. If heated very slowly in a Mohr's apparatus, Read January 14. See Abstract, page 86. † Proceedings, vol. xii. p. 633. munjistine sublimes in golden scales and broad flat needles of great beauty; these have all the physical characters and the same composition as the original substance. If the sublimation be continued for a long time at the lowest possible temperature consistent with its volatilization, the whole of it is obtained with scarcely any loss. The following are the results of the ultimate analysis of different samples of munjistine : I. 314 grm. of munjistine yielded ·732 grm. carbonic acid and ·106 grm. of water. II. 228 grm. of munjistine yielded ·535 grm. carbonic acid and 0765 grm. water. III. 332 grm. of munjistine yielded ·7795 grm. of carbonic acid and 1125 grm. of water. IV. 313 grm. of munjistine yielded 734 grm. of carbonic acid and ⚫1095 grm. of water. The carbon in No. I. is rather lower than that of the other three; this is owing to the specimen not being quite free from alumina; moreover it was burnt with oxide of copper, the others with chromate of lead. No. III. is the sublimed munjistine. All the analyses were made on specimens prepared at different times. Lead Compound. When aqueous or alcoholic solutions of munjistine and acetate of lead are mixed, a flocculent precipitate of a deep orange-colour falls, which changes to scarlet on the addition of a slight excess of acetate. The best method of preparing it is to dissolve munjistine in hot spirit and add to the filtered solution a quantity of acetate of lead insufficient to precipitate the whole of the munjistine, then to wash thoroughly with spirit, in which the lead compound is but slightly soluble, and dry first in vacuo, and then in the water-bath. I. 836 grm. lead compound gave 407 grm. oxide of lead. V. 2705 grm. lead compound gave 3445 grm. of carbonic acid and ⚫0445 grm. water. VI. 5350 grm. lead compound gave 6830 grm. carbonic acid and ⚫0920 grm. water. Theory. I. II. III. IV. V. .... VI. 34.73 34.82 1.82 .... 1.83 1.91 025 =200 14.55 .... .... .... 6РЬО 669•6 48.70 48.70 48.32 48.50 48.38 All the specimens were prepared at different times, except IV. and V., which are analyses of the same specimen. The lead compound therefore seems to approach nearly to the somewhat anomalous formula 5(C1 H ̧ O ̧) +6PbO, being a basic lead-salt; it is, however, perfectly analogous to the lead compound of purpurine, 5(C1, H; O5) +6PbO, described by Wolff and Strecker*. 18 From these analyses of the lead compound and also from the ultimate analyses of munjistine itself, it is pretty evident that its true formula is C1 H, O.. B Neither sublimed munjistine nor that obtained by crystallization from alcohol, when dried at the ordinary temperature in vacuo, loses weight at 110° C. It is not improbable, however, that the gelatinous uncrystallizable precipitate, which separates on the cooling of boiling saturated aqueous solutions of munjistine, is a hydrate. From some experiments made on a considerable scale, I find that ordinary madder does not contain any munjistine. In order to ascertain this fact, a considerable quantity of garancine from Naples Roots, and likewise some which had been subjected to the action of high-pressure steam according to Pincoff and Schunck's process, were treated with boiling bisulphide of carbon, and the product obtained on evaporating the bisulphide repeatedly extracted with large quantities of boiling water; the solution, when acidulated with sulphuric acid, gave an orange-red precipitate from which I was unable to obtain any munjistine. Professor Stokes succeeded, however, in detecting the presence of alizarine, purpurine, and rubiacine in it †. The production of phthalic acid from alizarine, purpurine, and munjistine, together with a comparison of their subjoined formulæ, indicates the very close relationship between these three substances, the only true colouring principles of the different species of madder with which we are acquainted. Two other very convenient sources of phthalic acid are-first, the dark red resinous matter, combined with alumina, which is left undissolved by the bisulphide of carbon in the preparation of munjistine; secondly, the large quantity of green-coloured resinous matter which remains behind after extracting the alizarine from Professor Kopp's so-called "green alizarine" by means of bisulphide of carbon. I have repeated Marignac's and Schunck's experiments of distilling a mixture of phthalic acid and lime; and, like both of these chemists, I observed a quantity of very aromatic benzol to be produced, which, by the action of strong nitric acid, readily yielded nitrobenzol, and from this, by the action of reducing agents, aniline. The only impurity in the benzol from phthalic acid appears to be a minute * Annalen der Chemie, lxxv. p. 24. He has since informed me that he has succeeded in demonstrating the absence of munjistine. quantity of an oil, having an aromatic odour, resembling that produced from cinnamic acid by the action of hypochlorite of lime. Tinctorial power of Munjistine and Munjeet. Prof. Runge stated, in 1835, that munjeet contains twice as much available colouring matter as the best Avignon madder. This result was so unexpected, that the Prussian Society for the Encouragement of Manufactures, to whom Professor Runge's memoir was originally addressed, referred the matter to three eminent German dyers, Messrs. Dannenberger, Böhm, and Nobiling. These gentlemen reported, as the result of numerous and carefully conducted experiments, that so far from munjeet being richer in colouringmatter than ordinary madder, it contained considerably less. This conclusion has been confirmed by the experience of my friend Mr. John Thom, of Birkacre, near Chorley, one of the most skilful of the Lancashire printers. From a numerous series of experiments I have just completed, I find that the garancine from munjeet has about half the tinctorial power of the garancine made from the best madder, viz. Naples Roots. These, however, yield only about 30 to 33 per cent. of garancine, while munjeet, according to my friend Mr. Higgin, of Manchester, yields from 52 to 55 per cent. Taking the present prices therefore of madder at 36 shillings per cwt., and munjeet at 30 shillings, it will be found that there will be scarcely any pecuniary advantage in using munjeet for ordinary madder-dyeing. The colours from munjeet are certainly brighter, but not so durable as those from madder, owing to the substitution of purpurine for alizarine. There is, however, great reason to believe that some of the Turkey-red dyers are employing garancine from munjeet to a considerable extent. When this is the case they evidently sacrifice fastness to brilliancy of colour. By treating such a garancine with boiling water, and precipitating by an acid in the way already described, its sophistication with munjeet may very readily be detected. The actual amount of colouring matter in munjeet and the best madder is very nearly the same; but the inferiority of munjeet as a dyestuff results from its containing only the comparatively feeble colouring matters, purpurine and munjistine, only a small portion of the latter being useful, whilst the presence of munjistine in large quantity appears to be positively injurious. So much is this the case, that when the greater part of the munjistine is removed from munjeet-garancine by boiling water, it yields much richer shades with alumina mordants than before. PURPUREINE. Action of Ammonia on Purpurine. When purpurine is dissolved in dilute ammonia and exposed to the air in a vessel with a wide mouth in a warm place for about a month, ammonia and water being added from time to time as they evaporate, the purpurine almost entirely disappears, whilst a new colouring-matter is formed which dyes unmordanted silk and wool of a fine rose-colour, but is incapable of |