1897 - 98 .] Dr D. F. Harris on Spectroscopy of Haemoglobin. 199 
I had the opportunity of studying the urine in the rare disease, 
^melanuria (melanotic sarcoma). Examined without dilution the 
dhrown-black fluid cut out all light except some red, and hence had 
no characteristic appearance ; on dilution, it became so like urine 
with bile or carbolic acid, that the spectroscope cannot be said, in 
such a case, to be of much service. 
Glacial acetic acid deepened the tint of the band in the dilute 
specimen ; KHO had a similar effect. 
XI . — On Carbon-Dioxide-Hcemoglobin. 
I was led to look a little into this pigment from finding that 
defibrinated blood, which has been shaken up in a 1 \ litre vessel full 
of pure C0 2 gas, no longer gives the two bands of Hb0 2 , and is of 
the true purple or 4 venous ’ hue. Further, if C0 2 be passed through 
some defibrinated blood for some minutes, so as to be thoroughly 
mixed with it, fully reduced HbO can be seen, though not 
without trouble, on account of the difficulty of preventing re- 
oxygenation in our attempt to examine it. The following device 
succeeded. A stream of the gas was made to bubble up through 
the blood in a haematinometer, and the froth examined in a strong 
light. A very beautiful phenomenon was seen : an intact bubble 
gave a single-banded spectrum, but the instant it had burst it was 
•oxidised, and yielded the two bands of Hb0 2 . The pellicle of the 
bubble was thin enough to allow sufficient light to pass to form a 
spectrum, while the bubble bursting upon the glass gave for a 
moment a smear of oxidised pigment before it drained itself down 
into the fluid below. The rapidity of the oxygenation was very 
notable. 
Quite otherwise is the behaviour of a dilute solution of Hb0 2 . 
I diluted defibrinated sheep’s blood till it gave the spectrum of 
Hb0 2 of 1 per cent., and for 2J hours passed through it a vigorous 
stream of C0 2 gas. The dilution had destroyed the red corpuscles by 
their having imbibed water and burst, so that under the microscope 
not a red disc was to be seen. At the end of 2 J hours the Hb0 2 was 
quite unreduced and had nothing of a venous hue. Thus, in order 
that C0 2 may reduce Hb0 2 , the physiological integrity of Hb0 2 
and the morphological condition of the red corpuscle must both be 
uncompromised. Does C0 2 * unite ’ with the red discs ? Presum- 
