On the chromatology of some British sponges / by C.A. MacMunn.

  • MacMunn, Charles Alexander, 1852-1911.
Date:
[1888]
Catalogue details

Licence: Public Domain Mark

Credit: On the chromatology of some British sponges / by C.A. MacMunn. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    coloured at first red-brown, later deep, dark violet, and the acidulated alcohol extract assumes a brown-yellow colour, which cannot be removed by stronger acidulation. Krukenberg then goes on to show that the darkening of this pigment occurs under different circumstances to those which obtain in the darkening of the lymph of Hydrophilus, for in the latter case melanosis is prevented by heating to 54°C, whereas in Aplysina heating brings it about, as it at once blackens at a boiling temperature, which blackening requires in other cases a long exposure to oxygen. The acid solutions however are not thus changed by heat. Aplysilla sulfurea likewise contains a similar pigment: a uranidine. Krukenberg assumes the presence of an oxidation ferment in Hydro- philus lymph, whereas in Aplysina &c. he supposes the ferment to exert a reducing action, which inhibits1 the production of the dark colour: this reduction ferment is destroyed by boiling; hence the darkening which then takes place. The solutions of aplysinofulvin are free from bands. I may now briefly refer to Krukenberg's observations on the lipochromes of sponges before giving my own results. Sometimes, he says, we can easily recognise the bands of these lipochromes in solutions which are capable of dissolving them, sometimes however they are rendered invisible by the presence of other colouring matters. Saponi- fication enables them to be prepared in a purer state, a process which however decomposes the chlorophylloid pigments, which Krukenberg calls the hepatochromatic colouring matters, but he found that bands of the lipochrome in unsaponified extracts corresponded with bands of similar solutions from saponified extracts. A lipochrome which in the solid state coloured itself deep blue with nitric and sulphuric acid, but remained unchanged with iodine, which was soluble in the usual lipochrome solvents and appeared to be identical with lipochrin, was found in Tedania muggiana. In petroleum-ether it gave one band covering F, and another placed between F and G (after saponifying). The ether solutions showed however, after the petroleum-ether had extracted all colouring matter soluble in it, only one band like that of Kuhne's rhodophan, but differing from its band. Another pigment which occurred in red flocks and was left undissolved by the ether was insoluble in alcohol, chloroform, and bisulphide of carbon, but dissolved in acetic ether and dilute alkalies, and by damping with- acetic acid became a deep purple, and then dissolved in bisulphide with a purple 1 I use the word inhibit here, as this expresses the sense of Krukenberg's statements more tersely than an exact translation.