750 
e.g. to the conclusion that the yellow pigment of the body-fat, milk- 
fat, and blood-serum of the cow is identical with carotin, whereas 
the yellow colouring matter of the egg-yolk, body-fat and blood- 
serum of fowls corresponds with xanthophyll. He also demonstrated 
that these pigments in animals are of alimentary origin. Finally 
that in the cow’s intestine carotin is resorbed well nigh exclusively, 
whereas in the fowl’s intestinal canal only xanthophyll is resorbed 
almost to the exclusion of other pigments. 
Our prolonged investigation of lipochrome in the serum of the 
human blood led us to study some of its qualities more in detail. 
As already stated in the paper referred to above’), we had 
observed that the lipochrome pigments behave differently in man 
and in the cow towards ethylalcohol. When we precipitate cow’s 
serum with 2 vol. of alcohol and when centrifugalizing the preci- 
pitate, the lipochrome can be extracted from it with ether. The 
cow’s pigment, then, is nearly soluble in 64 perc. alcohol. When 
we submit human serum to the same process, we generally fail to 
extract pigment with ether from the protein precipitate; it can be 
obtained when we precipitate 1 vol. of human serum by an equal 
volume of alcohol. It appears then that the human lipochrome is 
often soluble in 64°/,, but invariably insoluble in 48 perc. of alcohol. 
This different behaviour of lipocbromes towards 64°/, alcohol we 
purposed to examine. 
First of all we ascertained in which of the two groups of caro- 
tinoids, as established by Wuttistarrer, the pigments from carrots, 
ege-yolk, fowl’s serum, cow’s serum and human serum, have to be 
placed. 
The materials to be examined are treated with 96 °/, ethylalcohol ; 
subsequently with petroleum-ether. By adding an appropriate quantity 
of water all the lipochrome passes over to the petroleum-ether, which 
floats on the surface as a limpid, gold-yellow layer. 
This layer is pipetted off. It contains besides the pigment, also 
fats, cholesterin and presumably still other substances. The fats are 
removed by saponification, the cholesterin is precipitated by digitonin. 
What remains is an incompletely purified solution of lipochrome in 
petroleum-ether. When adding to this fluid methylaleohol (90°/, or 
stronger) the pigment will pass over to the lower methylaleohol 
layer, if we have to do with xanthophyll, to the benzene layer in 
the case of carotin. Following WittstArtrer’s example we always 
used methyl-alcohol for this process; ethylalcohol proved to be 
‘) Deutsch. Arch. f. klin. Mediz., loc. cit. 
