749 
Daucus carota, while ArNnaup showed in 18857) that a yellow 
pigment in the green parts of plants is identical with the carotin 
from carrots. ARNAUD made an extensive study of carotin and esta- 
blished that it is an unsaturated autoxydable carbohydrate. His 
analysis and further inquiries produced the empiric formula C,,H,,. 
Ever since many inquiries into these pigments have been undertaken. 
Latterly they have received Wu.rsrätrer’s *) attention. He established 
in accordance with the assumption of previous inquirers that plants 
contain different pigments which — as Boropin*) had observed — may 
be divided into two large groups. The pigments of the first group, 
to which carotin belongs, are rather easy to dissolve in benzene, 
hardly so in alcohol. The second group is represented by xantho- 
phyll, which can readily be dissolved in alcohol, less readily in 
benzene. Either of these substances could be obtained in pure, erystal- 
line condition. The elementary analysis, the determinations of mole- 
cular weight, and the analysis of iodine-addition products yielded the 
formula C,,H,, for carotin and C,,H,,O, for xanthophyll. WitisTarrer 
also corroborated that the two carbohydrates are highly unsaturated 
and autoxydable. They are very sensitive to acids, but are not 
attacked by alkali. 
Also in animal produets, particularly in the egg-yolk, in the serum 
of animals and men, former observers have found lipochrome pigments 
(KRUKENBERG, THupicum, SCHUNCK, Kürne) and have published interesting 
communications about them. They usually term them luteins. To 
Witistatter and his co-workers we are indebted for considerable 
advance in this respect. It appeared that also the animal lipochromes 
or carotinoids may be divided into two groups according to their 
relative solubility in benzene and alcohol. 
Winistarter’s pupil Escuer managed to separate pure carotin 
from the corpus luteum of the cow. WursrÄärrer, in conjunction 
with Escner, has obtained lutein from the egg-yolk, and established 
that it is quite identical with the xanthophyll from plants, with a 
difference only in the melting-point. 
Some years ago a series of papers appeared from the American 
Algricultural-Chemist Patmer*). We shall frequently refer to this 
work, but it may be expedient to state here what we deem to be 
the chief result of Parmer’s work. The American researcher comes 
1) A. Anmnaup. C. R. Ac. Sc. 100, 751, 1885, and 102, 1119, 1886. 
%) Wittstitrern u. Srou, Untersuch. über Chlorophyll. Berlin 19138. 
5) Quoted from Wittstitten. 
*) Patmen, The Journ. of biolog. Chem. 1915—1919. 
