596 
DE. A. GAMGEE ON THE ACTION OE NITEITES ON BLOOD. 
come in contact ; whereas it is only after some time that the further reducing-action of 
the sulphide makes itself manifest. 
Obs. III. Five cub. centims. of freshly defibrinated blood of the Ox were diluted to the 
volume of one litre, and the solution was then examined in a hollow prism. A layer of 
solution two centimetres thick was examined. The spectrum of this solution was as 
follows : — 
Band a 60-65 
Band (5 72-76 
Extent of spectrum . . . 30-110 
One cub. centim. of a solution of nitrite of potassium of unknown strength was added 
to 200 cub. centims. of the above blood-solution. Almost instantaneously the bands 
became much fainter. About two minutes after the addition of the nitrite, on exa- 
mining a stratum two centimetres broad, the two absorption-bands had become almost 
invisible, appearing as mere shadings of the spectrum. There was a very faint band 
with its centre at 50. On examining thicker strata of fluid the original bands could be 
seen more distinctly, and the band in the red was very well marked. A solution of 
ammonia was added to the fluid. The red band disappeared at once, and the two bands 
became more intense. The orange was observed to be shaded, a faint absorption-band 
appearing to overshadow it and to join the band a; as in other observations to deter- 
mine this point it was impossible for me to decide whether the band in the orange was 
separated from the band « by any unshaded portion, i. e. whether it was an absolutely 
separate band. On bringing a soda-salt into the flame of the lamp whose light was 
passed through the blood-solution and examined, the yellow line was seen to be bounded 
above by a very marked absorption-band extending from 60 to 65, and below by the 
shadowy but distinct band in the orange (a'). The following observations were now 
made : — 
a . . 60-65 
a! . . 56-59 
j3 . . 71-78 
On now passing a long pipette charged with sulphide of ammonium to the bottom of 
the fluid, the sharply defined absorption-band of O-Hb appeared. 
a . . 60-65 
/3 . . 70-78. 
The bands were very much blacker than before, and the absorption-band in the 
orange had disappeared. After some time the fluid had assumed a purple tint, indi- 
cating reduction. On then examining it a single broad band, that of reduced haemo- 
globin, was seen. This band extended from 65-74. The fluid in the prism was now 
poured into a beaker and thoroughly shaken with air, then reintroduced into the prism 
bottle. The colour had now changed again from purple to red, and the following 
reading obtained: — 
a . . 61-65 
j 8 . . 70-78 
