506 
substances is indeed highly probable. At present I am in the posi- 
tion to prove it absolutely. 
The difficulties of preparation of pure cholehaematin, appeared 
to me under the conditions of my laboratory unsurmountable but 
they have been. as it proved, overcome elswhere In a highly in- 
teresting paper read before the Academy of Sciences of Vienna. 
Loebisch and Fischler!) deseribed a substance, isolated from the 
bile of herbivora under the name of bilipurpurin (The quantity 
of bile used amounted to 100 litres!). Although the deseription of 
this substance as given by these authors does not agree in all 
particulars with that of my phylloerythrine, the similarity of the 
properties of both substances appeared sufficiently great to awaken 
the wish to compare both substances by direct observation. Prof. 
Loebisch was kind enough to send me by my request a minute 
but quite sufficient quantity of bilipurpurin, and a careful compa- 
rison of its optical properties with those shown by phylloerythrin 
and by cholehaematin proved conelusively that all these substances 
are indeed identical. 
The erystals of bilipurpurin are quite identical with those of 
phylloerythrin. The preparation sent to me by Mr. Loebisch eon- 
tained not only erystals eseribed by him and eloser investigated 
by Cathrein. but also rhombie plates with blunted corners which 
I have found to be characteristie of phylloerythrine. On the other 
hand some of my new preparations of phylloerythrine contain elon- 
gated plates, similar to those depieted by Loebisch. 
The optical properties of bilipurpurin and phylloerythrine are 
absolutely identical. In my former communication ?) I mentioned 
that concentrated solutions of phylloerytrine in acetie acid cause 
a spectrum with four bands, one of which, near the C-line, is 
extremely faint. A direct comparison of such solution with a bili- 
purpurin solution showed that, given equal concentrations, the bands 
in both cases are placed in exactly the same position; in fact it 
is impossible to distinguish one spectrum from the other. More 
dilute solutions do not show the faint band in the orange. The 
colour of both substances is of course identical; cherry red is, 
may be. the most suitable description for it. Both solutions show 
1) Sitzungsber. der kaised. Akad. der Wissenschaften in Wien. 62 (11) 159. (1903). 
?) This Bulletin 1903, 638. 
