746 
stances has interested one of us for a series of years, but the sub- 
ject presents very great difficulties not only on account of their 
great susceptability towards chemical and physical influences but 
also because of the difficulties in obtaining larger quantities for 
examination. Bixin is a substance that may be obtained at a not 
very excessive price and in greater quantities, and we thought 
therefore that the examination of bixin might be of some use in 
tackling the problem of lipochroms. As it proved the study of 
bixin presents also very great difficulties and that its constitution 
must be rather complicated; we did not succeed in elearing it up. 
nevertheless we intend to publish our results having discovered 
a few new facts and succeeded in improving old methods which 
may fascilitate further researches. 
Method of preparation of pure bixin. 
The oldest known method described by Etti, said to yield ery- 
stalized bixin did not prove successful at our hands. Zwicks me- 
thod we found quite reliable but tedious. This author proceeds as 
follows. Commercial Orlean colour is first dryed on a water bath, 
the powdered product is then extracted with boiling cehloroform, 
filtered and the chloroform evaporated. The residue is dryed on 
the water bath and extracted in a Soxhlet apparatus first with 
ligroin and then with chloroform. During the process of extraction 
Zwiek noticed the formation of crystals, which were recrystallized 
again twice or three times from chloroform. The melting point of 
these crystals is according to Zwick 189°C. 
We proceeded as follows. Orlean colour purchased from Messrs 
Alder & Co of Vienna, in the form of a brick red paste was dryed 
thoroughly on the water bath and the dry substance obtained 
extracted in the cold with chloroform during 2 days. The first 
extract was drawn off, the chloroform regenerated and used again 
for the second extraction of the raw material. The residue of the 
first extract represents a soft, resinous mass, which will not solidify 
even after prolonged drying on the water bath; it contains most 
of the organie impurities of the crude colour and some bixin, but 
we found it not worth while to try to isolate the latter from this 
first fraction. The second chloroform extract whether obtained in 
the cold or at the boiling point of chloroform gave on evaporation 
a brittle dark red brown mass, which yielded without much trouble 
