219 
bands may be placed in identical order: III, II, IV, I, the band I 
being the faintest. We see therfore that so far the similarity of 
the optical properties of both solutions is indeed remarkable. There 
is however also a difference in the spectra which is perhaps of 
not much importance. I found that the above cholehaematin solu- 
tion eauses in addition to the four bands mentioned, a fifth placed 
Mac Munn noticed such a band in the erude bile solutions, but 
does not mention it as belonging to the pure cholehaematin !). It 
is therefore quite possible that my cholehaematin solutions were 
not as pure as those prepared by Mae Munn, they might for in- 
stance contain some urobilin, which causes a band in the spectral 
region named. 
I was especially anxious to examine the absorptions eaused by 
both eolouring matter in the invisible part of the spectrum, because 
they are especially characteristie for all derivatives of the blood 
colouring matter and of chlorophyll. Phylloerythrine is characte- 
rised as I have shown by two bands, a broad and dark one in 
front of the ka line and fainter band just behind that line. Chole- 
haematin causes a similar absorption, but of the two bands the 
darker and broader is placed behind the ke line. An absolute 
identity is therfore also wanting in this case what may be also 
due to impurities contained in the erude cholehaematin solution at 
my disposal. 
The identity of cholehaematin and phylloerythrine is according 
to the above results no doubt highly probable, but not absolutely 
certain. The irreproachable proofs can be supplied only by a com- 
parison of the pure substances, isolated in the erystalline state. The 
diffieulties in the preparation of pure phylloerythrine have been 
overcome. Not so in the case of cholehaematin. As far as I can 
judge a thousand of sheep biles would have to be worked up in 
order to isolate it in the pure state. a task which at the present 
time is beyond my powers. Should it at some future time be 
possible to surmount the difheulties and to prove that the two 
substances in question are really identical, there eould not be any 
doubt that some of the chlorophyll or one of its derivatives is 
!) Unfortunafely, Mac Munns original papers are not accessible to me. The 
above data I owe to Gamgee’s excellent book mentioned before. 
