520 
are easily soluble, slowly in glacial acetic acid. Witb concentrated 
or somewhat dilute sulphuric acid, for example 66'/,°/,, they are 
not coloured blue, but green (Kr. et V. 326). The colour never 
resembles the blue colour which the crystals of earotinoids assume 
with sulphuric acid, and which never shows a green, but sometimes 
a slightly violet tint. The green-coloured crystal aggregates are soluble 
in sulphuric acid. The brown crystal aggregates are also coloured 
green by concentrated hydrochloric acid (specifie gravity = 1.19); 
afterwards they dissolve slowly. With concentrated nitric acid they 
are not, as is the case of carotinoids, temporarily coloured blue; they 
deliquesce and form globules, which when gently warmed, gradually 
become colourless and presumably consist of phytol. Nor do they, 
like carotinoids, become temporarily blue in bromine water; the 
brown colour at first remains unchanged. Towards caustic potash 
the brown aggregates of crystals also behave quite differently from 
the crystals of carotinoids; they are entirely soluble in it; they also 
are completely soluble in dilute alcoholic caustic potash, as, for 
example, in Mouiscu’s reagent, in which the crystals of carotinoids 
are of course insoluble. Since they leave nothing behind on solution 
there is no reason for thinking that they contain carotinoids. 
The behaviour of the brown aggregates towards reagents shows 
that they are composed of a chlorophyll derivative. Phaeophytin *) 
gives the same reactions, and sometimes more or less clearly shows 
crystalline structure. Tammes and Konr have confused carotin with a 
chlorophyll derivative. Tammes’ drawing N°. 22 of Elodea canadensis 
in particular clearly shows that such a confusion has taken place. 
In each cell a number of brown, round crystal aggregates are figured 
attached to and on the chromatophores. The crystalline structure is 
not indicated in the figure, but is not always easily distinguished 
in the full cells. Besides these crystal aggregates, I found in many 
cells, though not in all, red aggregates of crystals which resemble 
carotin and which are coloured blue by concentrated or somewhat 
dilute sulphuric acid, namely of 76°/,. These crystal aggregates are 
however not figured by Tames, nor are they mentioned. 
Now it is somewhat explicable why Tames’) obtained negative 
results with yellow variegated, yellow autumn and etiolated leaves: 
These objects or the yellow parts of them contain no chlorophyll 
and are therefore unable to produce brown crystal aggregates of a 
chlorophyll derivative. But this does not, however, clear up every- 
+) R. Wittsrérter und F. Hocueper, |. c. p. 222 and 223. 
*) le. p. 220. 
