1897 - 98 .] Dr D. F. Harris on Spectroscopy of Haemoglobin. 195- 
7, Saffranine . — Soluble in water; in strong solution it very 
closely resembles HbO, except that the one broad band does not 
approach the D line so closely as in the case of the blood-pigment ; 
no blue light is transmitted in either case. Upon diluting saffranine 
all the blue light passes, and the band locates itself much more to 
the right, so as to resemble the spectrum of urinary or biliary 
pigment. 
8. Eosine . — In dilute solution this gives a band in the green at 
b very similar to the fourth and most distinct band of alkaline 
hsematoporphyrin. 
VII , — The Spectroscopic Recognition of Blood-Stains. 
Quite fresh blood-stains, e.g., before drying upon a handkerchief, 
yield with transmitted light the spectrum of Hb0 2 . Stains more 
than an hour old, and therefore quite dry, yield two bands; but if 
brown , give no bands, as hsematin must be soluble and transparent 
to do this. Blood-stained filter-paper fourteen days old, when dry, 
gave the Hb0 2 spectrum on the edge of the paper ; after four 
months, and only after being wetted, that of acid met-hsemoglobin. 
VIII . — Circulating Blood. 
One must be prepared to find, even when the spectrum of 
circulating blood can be obtained, only one band, as indicating 
such a thickness of blood that the opacity allows of the ap- 
pearance of only one band. If, for instance, the hand be held up 
before a powerful light, or to the sun at noon, one can see by the 
spectroscope, directed to the crimson glow between the fingers, a 
one-banded spectrum as of Hb0 2 greater than 1 per cent. ; similarly, 
light which has passed through the human pinna, or been reflected 
from the nail, or from the rabbit’s fundus oculi, yields the same 
spectrum. If one uses the semitransparent ear of an albino 
rabbit, the blood sheet is just thin enough to yield the two-handed 
spectrum, which fades into the one-handed spectrum of the re- 
duced pigment if one constricts the base of the ear for 30". A 
two-banded spectrum can be seen if the frog’s web (prepared as- 
for microscopic examination) be interposed between the light and 
a spectroscope. If a ligature be now tightly tied round the thigh,. 
