404 Transactions. — Chemistry. 



Art. LXYI. — Xotes on the Colouring Matter of Hrematococcus sanguineus. 



By Llewellyn Powell, M.D. 

 [Read before the Philosophical Institute of Canterbury, 2nd July, 1874.] 



At the April meeting of the Society, a short paper, by Dr. Berggren, of 

 the University of Lund, on the colouration of wool by Ilcematococcus san- 

 guineus, was read.* A specimen was shown beneath the microscope exhibiting 

 the dried and deformed cells of the alga nearly colourless, the fibres of wool 

 being tinted of a pinkish hue. I have thought that some observations of my 

 own on the colouring matter of Ilcematococcus may be worth recording in 

 connection with Dr. Berggren's paper. 



The alga consists of a diffuse formless frond found in damp places, beneath 

 the drip of the eaves of houses, and such like. It has a dull brownish red or 

 maroon tint, and very closely resembles a patch of half-dried blood ; this 

 resemblance is embodied in the various names — Hcematococcus sangidneicSy 

 Palmella cruenta, and the popular name, gory dew ; when quite dry the 

 colour changes to a pinky lilac or peach colour. The frond consists of 

 numberless discrete spherical cells embedded in a structureless matiix ; the 

 cells have beneath the microscope a pale orange red tint, the matrix being 

 colourless. 



"Water, whether cold or at a boiling temperature, appears to have no action 

 upon the colouring matter. Solution of ammonia, or other alkali, immediately 

 changes the colour of the cells to a bright olive green. 



If the frond be boiled in alcohol the spirit acquires a deep green tint, 

 exhibiting the characteristic absorption spectrum of chlorophyll — a sharply 

 defined black band in the extreme red. 



Glycerine extracts at ordinary temperatures a colouring matter having 

 definite characteristics. The solution of this principle in glycerine is dichroic, 

 having by transmitted light a very beautiful carmine tint, in fact the hue is 

 scarcely distinguishable from a very dilute ammoniacal solution of carmine. By 

 reflected light, however, there is a very remarkable difierence, for, whereas 

 the carmine solution appears unchanged, the solution of the colouring principle 

 of the Iloimatococcus exhibits a luminous orange cloudiness ; by artificial light 

 this is dingy yellow. 



The colouring matter gives a definite absorption spectrum, consisting of a 

 broad band commencing with a well-defined dark edge a short disti\nce nearer 

 the blue than the sodium line D, or about the centre of the fourth black band 

 of Beale's absorption scale, and shades off gradually to E, where it loses itself. 

 The spectrum may be advantageously compared with that of the solution of 

 carmine, which, with an almost exactly similar tint, gives however a totally 

 different spectrum, consisting of three not very well-defined bands. 



• Sec Art. LV. 



