Page:Proceedings of the Royal Society of London Vol 69.djvu/326

310 becomes nearly colourless, and deposits rosettes of lustrous crystalline needles, presumably of unchanged substance ; so that it appears no sulphonic acid is formed in this reaction, the colour of the solution in sulphuric acid being due probably to a loose combination of the sub- stance with the acid. The substance is soluble in boiling aniline ; the solution is dull red, and gives with alcohol a deposit of brilliant needle-shaped crystals, the filtrate from which shows the same spectrum as the solution in acetic acid. The substance is insoluble in aqueous caustic potash, but dissolves in alcoholic potash, giving a yellow solution.

Absorption Spectra of Scatocyanin Solutions.

1. Scatocyanin in glacial acetic acid.

2. The same in concentrated sulphuric acid.

There is another substance of definite character and assuming a crystalline form which I have obtained, though not always, along with the preceding. Having treated the faeces of a cow that had lived for some time on green vegetable food, with acidulated alcohol (seventeen parts of rectified spirit to three of sulphuric acid, the mixture prescribed for the preparation of so-called stercobilin), I added water to the filtered extract and shook up with chloroform. The chloroformic liquid after separation was evaporated, when it left a brown syrup. This, treated with boiling alcohol, dissolved in part, a semi-crystalline pink residue being left undissolved, which, after separation, was found to be soluble in boiling acetic acid with a crimson colour, and consisted doubtless of Scatocyanin. A further quantity of this was deposited on again evaporating ; on further evaporation, the filtrate left a thin brown syrup which was mixed with a large quantity of alcohol. On standing, a voluminous crystalline deposit separated, which was filtered off and slightly washed with alcohol.

The following are the chief properties of the substance so prepared : When dry it has the appearance of a dull red mass of crystalline needles. Heated on platinum, it melts easily to a brown mass, solidifying again on cooling ; on further heating, it gives off red fumes