694 
different crystals are then distinguished very clearly with sulphuric 
acid of 66'/,°/,, only the orange-yellow crystals become blue. 
If preparations with crystals separated by the potash method are 
placed on the slide in a solution of chloralhydrate (7 in 10) then 
after a time, for example, 1°/, hours, the aggregates appeared much 
changed; the orange-yellow crystals had been dissolved and the red 
needles or small parallelograms remained behind, sometimes still 
united. After 24 hours they had not wholly disappeared from the 
preparations. 
With soap-spirit also (Pharm. Nederl. Ed. IV, without oil of 
lavender) a great difference in solubility was proved. After being one 
day in soap-spirit the orange-yellow crystals had disappeared from 
the preparations, whilst the red remained behind. 
I obtained a still more striking result with a solution of phenol 
in glycerine (3 to 1). If this mixture is allowed to flow under the 
cover-slip, the orange-yellow crystals are seen to dissolve quickly 
whilst the red ones are unchanged even after 24 hours. 
The investigation of the orange-yellow and red crystats can be 
facilitated in the following manner. Leaf fragments are placed for 
two hours in a 10 °/, solution of oxalic acid and then put into 
Mouiscn’s reagent. In the tissue large red and yellow erystal-aggre- 
gates are thus formed, which can easily be studied. 
On consulting the paper of WitistArrer and Mike’) on carotin 
and xanthophyll, we must conclude that, of the crystals described, 
the red are carotin and the orange-yellow xanthophyll. 
As in the leaves of Urtica dioica so in many other cases, in 
flowers, leaves and algae, I have been able to distinguish yellow, 
orange-yellow or orange-coloured crystals and red or orange-red ones, 
of different shape, which behave differently towards reagents and 
solvents and indeed in a more or less corresponding way. I do not 
doubt that in all these cases the plant contains different carotinoids 
side by side, in many cases probably a carotin together with a 
substance which belongs to the xanthophylls. I think it not 
improbable that the same carotin and the same xanthophyll are 
often found together, but I also consider that in a number of cases 
another carotin or xanthophyll is present. WILLsTATTER and EscueEr ”) 
have already established the presence, in the fruit of Solanum Lyco- 
persicum, of a carotin, lycopin, differing chemically from Daucus-carotin. 
1) 1. ce. 
2) RicHarp Wi.uisTATTER und Herter. H. Escuer, Ueber den Farbstoff der 
Tomate, Hoppr-SryLer’s Zeitschr. fiir Physiol. Chemie, 64. Bd. 1910, p. 47. 
