COLOURING MATTER DECOMPOSITION OF OSCILLARIAS. 335 
water, but produced a blue solution by the addition of mu- 
riatic acid. 
To experiment with reagents — the liquid of the last mace- 
rations was chosen, which from all appearances no longer 
contained a portion of the mineral water. The changes pro- 
duced by these reagents were observed at the termination of 
eighteen hours. 
With alcohol a reddish purple flocculose precipitate was 
formed. 
Tincture of galls produced a deep blue precipitate, the su- 
pernatant liquid was yellow and clear. 
Nitrate of silver occasioned a dirty brown precipitate; and 
complete decolouration. 
Acetate of lead afforded an abundant white precipitation, and 
sulphate of copper a feeble sky blue precipitate. 
Alum and carbonate of potassa formed a copious white pre- 
cipitate with a violet tint. 
With the protonitrate of mercury a very beautiful violet 
precipitate was thrown down, and complete decolouration 
with corrosive sublimate; the precipitate was copious, floccu- 
lent and of a beautiful deep blue. Muriatic acid heightened 
the colour, sulphuric acid yielded a precipitate slightly violet, 
and lime water one of a white colour and flocculose. 
It may be inferred with much apparent truth, from the 
chemical properties which have been described, that the cause 
of the colour is attributable to a substance closely allied to al- 
bumen. The manner in which it is affected constitutes a 
marked distinction between it and the known blue vegetable 
colouring matters; thus it is in a manner the opposite of He- 
liotrope in its properties. It is equally dissimilar to the blue 
colouring matter of flowers, in the effects which acids produce 
upon it; its want of durability distinguishes it from indigo. 
This colour on the contrary resembles the blue colour which 
MM. Caventou and Bonastre obtained from the white of eggs 
treated with muriatic acid: but in the liquid in question, no 
muriatic acid was present, and these authors do not mention 
that this colour appeared sometimes red and at others blue. 
