98 Schunck . — The Chemistry of Chlorophyll. 
fluorescence, may still hold in solution some phyllocyanin along 
with phylloxanthin ; the former is easily removed by shaking 
the solution with concentrated hydrochloric acid, this being 
repeated with fresh quantities of acid, until the latter takes up 
no more colour. The process must be conducted rapidly, 
because by prolonged contact of its solution with hydrochloric 
acid phylloxanthin undergoes a change which results in its 
becoming soluble in the acid, the latter even when quite 
colourless becoming blue on standing from the surface down- 
wards, so as to make it seem as if under these circum- 
stances phylloxanthin were really converted into phyllocyanin. 
After removal of the phyllocyanin, the phylloxanthin solution 
still contains a large quantity of another impurity, which I 
have so far been unable to remove. This impurity is the fatty 
matter, which is always deposited along with the colouring 
matters when hydrochloric acid gas is passed into a solution of 
crude chlorophyll, and which in the process adopted remains 
for the most part dissolved in the ether. When the ethereal 
solution is slowly evaporated it leaves a quantity of long 
pseudo-crystalline needles, sometimes accompanied by small 
crystalline rosettes which are brown by transmitted light ; these 
consist of phylloxanthin, contaminated, however, with fatty 
matter. Solutions of phylloxanthin have a yellowish-green 
colour with a pronounced reddish tinge, and may be thereby 
distinguished from solutions of phyllocyanin which are more 
decidedly green. They show a spectrum of four bands only, 
that of phyllocyanin having five ; an admixture of the latter 
with phylloxanthin may therefore be easily detected. The 
four bands which appear on the addition of a little hydro- 
chloric acid to a solution of chlorophyll are due in my opinion 
to phylloxanthin, which is formed in the first instance ; the 
appearance of a fifth band after the prolonged action of the 
acid indicates the presence of phyllocyanin. Whether phyllo- 
xanthin by the continued action of acid is converted into 
phyllocyanin, or whether the two colouring matters are formed 
independently, but in succession from chlorophyll, or whether 
lastly the two owe their formation to two distinct sub- 
