387 
1896 - 97 .] Mr D. F. Harris on Hazmatoporphyrinuria. 
chief seat of the formation from hsematin of the immediate ante- 
cedent of urobilin there can he no doubt, for — 
(1) Increased destruction of red blood-discs in the liver, such as 
follows from injecting into the portal vein any substance which 
liberates Hb0 2 , leads to an increase of urinary pigment. 
(2) In pernicious anaemia much iron is deposited in liver cells, 
and the urobilin is increased, indicating an exaggerated destruction 
of Hb0 2 ; in such urines the band at F can be seen (without con- 
centrating the urine), sometimes pathological urobilin, a more de- 
oxidised pigment, is formed due to the abnormally intense de- 
oxidative hepatic katabolism of Hb0 2 . 
Since M‘Munn made urobilin by oxidising acid-haematin by 
per-oxide of hydrogen, and then briefly de-oxidising with sodium- 
amalgam, he has suggested that “ urobilin is formed by nascent 
oxygen in the tissues.” As to the modus operandi of its formation 
there are, then, two theories : (1) The reduction theory ; (2) The 
oxidation theory. Though most probably both reduction and 
oxidation occur in the formation of uroblin, neither is alone the 
method ; and as it was unsatisfactory to attribute the reduction to 
intestinal nascent H, so it is unlikely that nascent oxygen in the 
tissues performs the oxidation. The living protoplasm of the 
tissues craves oxygen for itself, and fixes it interstitially. If the 
liver is the great source of urobilin formation, it is, as we should 
expect, pre-eminently a region of c/e-oxidations. 
All other pigments are artificially produced by processes of 
more or less complete reduction, thus : — - 
(1) Haematin acted on by nascent H = Haematoporphyrin. 
(2) Haematin (but not bilirubin) acted on by zinc + H 2 S0 4 
to full reduction, yields pathological urobilin, inter- 
mediate stages in this process giving “ urobilinoidin” 
(le Nobel), the chromogen of urohsematoporphyrin. 
(3) Urobilin reduced yields pathological urobilin (para- 
urochrome). 
From these facts and other considerations we may follow 
M £ Munn in believing that the order of the pigments as to degree 
of de-oxidation is as under : — 
(1) Oxy -Haemoglobin. 
(2) Haemoglobin. 
