ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 469 



broken up into dark brown shreds, whilst the fluid remained colour- 

 less. No effect was produced by absolute alcohol or by ether, but 

 the colour in the fragments in sea-water diffused out to a considerable 

 extent in twenty-four hours. The fluid then was dark brown ; pres- 

 sure caused no separation of the colouring matter. 



Boiling caused the colouring matter to diffuse out quickly, and 

 on filtering the fluid it was found to be acid and of a dark brown colour. 

 The colour at once disappeared on the addition of strong sulphuric 

 acid ; strong nitric and strong hydrochloric acids produced the same 

 effect, but not so quickly. Strong caustic potash caused a reddish- 

 brown precipitate, but as the fluid consisted of sea- water, a portion of 

 the precipitate must have consisted of the hydrated oxides of lime 

 and magnesia in the water. 



As regards Cyanea and Awelia, neither pressure, boiling, nor 

 mineral acids, alkalies, alcohol, or ether, dissolved out the colouring 

 matter. The only way of obtaining it was to allow fragments tn 

 macerate in sea-water for about thirty-six hours. Then the fluid 

 became sky-blue when Cyanea was used, and slightly pink with 

 Aurelia. The colouring stuff could not be extracted from this fluid 

 by alcohol or ether, but was thrown down by an alkali. On adding 

 ammonia to any coloured infusion of jelly-fish, a copious precipitate 

 falls, which carries with it the whole of the colouring matter. After 

 filtration the fluid is quite colourless, and the colouring matter 

 remains on the filter. Again the precipitate is readily redissolved 

 by acid, and the colouring matter passes into a soluble state. It is 

 soluble therefore in an acid medium, but insoluble in an alkaline or 

 neutral medium. Now fresh jelly-fishes, so far as the author could 

 make out, were quite neutral to test paper ; he could not find any 

 alkaline reaction. But in the living jelly-fish we can scarcely 

 suppose that the colouring matter exists in the granular form simply 

 because the medium is alkaline or neutral ; all we can state is that 

 the medium is neutral, and the probability is that the colour stuff is 

 formed in the protoplasm of certain cells, just as pigment is formed 

 in the cells of the epidermis of many animals. After the death of 

 the jelly-fish, however, the body becomes slightly acid, the protoplasm 

 disintegrates, and the colouring matter diffuses out. During life a 

 muscle is slightly alkaline or neutral ; after death, when rigour sets 

 in, it becomes acid. 



The colouring matter was also examined with the spectroscope ; 

 it was found that infusion of Chrysaora gave no distinct absorp- 

 tion bands ; but the violet, blue, and a portion of the green were 

 absorbed, the other colours being slightly reduced in intensity. On 

 concentrating the fluid, the red, yellow, and what remained of the 

 green, became very dim, but no bands appeared. With Cyanea, how- 

 ever, an infusion gave two distinct absorption bands, one in the red, 

 and the other in the orange. The other blue colouring matters 

 hitherto met with in the animal kingdom are the blue colouring 

 matter obtained from Stentor cceruleus, described by Lankester,* which 

 gives two absorption bands nearly the same in position as those in 



* Quart. Journ. Micr. Sci., xxi. (1873) p. 139. 



