757 
Daucus carota (subsequent researches proved the same to hold good 
for xanthophyll) exposed to the sunlight, is decoloured by the ab- 
sorption of oxygen and after some time is completely decolourized. 
With our impure or incompletely purified solutions of pigments in 
alcohol and ether our results varied with the nature of the lipo- 
chrome and the solvent. After a close exposure to the quartzlamp 
the aqueous solutions are almost completely decolourized after 15—90 
minutes, the interval varying with the nature of the lipochrome and 
of the solvent. Contrariwise the native substances (egg-yolk, carrots, 
cows serum) are not decolourized under similar circumstances. It 
is evident, therefore, that with regard to sensitiveness to light, there 
is a difference between the native solutions of lipochromes and the 
colloidal aqueous solutions. 
