1897 - 98 .] Dr D. F. Harris on Spectroscopy of Hcemoglobin. 189 
sheep’s blood with its own volume of water, and to 140 c.c. of it, 
warmed to 35° C., add 5 c.c. of glacial acetic acid; stir and filter. 
This shows the characteristic band in the red. I find, with 
Stirling (2), that acid hsematin is incapable of reduction with 
Am 2 S. 
4. Alkali Hcematin . — To 140 c.c. of a '7 per cent, of Hb0 9 
while at 35° C., add a stick 2’5 cm. long of solid KHO ; stir, 
filter. 
This is a pigment not well adapted for demonstration on a large 
scale, ow r ing to the large amount of light cut out by its broad area 
of absorption in the orange, and to the very considerable dimming 
of all light to the right of F. 
5. Hcemocliromogen . — Of the above solution take 140 c.c. and 
dilute it to three times its volume, warm to 35° C., and add 15 c.c. 
of Am 2 S, when the dark olive-brown solution almost immediately 
changes to a ruddy tint; it must not be overheated. Being 
reduced alkali hsematin, a very striking experiment may he per- 
formed by oxygenating some of it and looking at its spectrum. 
The two characteristic bands in the green have disappeared and 
given place to that broad indefinite region of absorption charac-. 
teristic of the unreduced alkali hsematin. If, however, this area 
of dimming be now scrutinised, in a few seconds, towards its right 
border, the ghost of a dark band will be seen to form, and to 
become every moment more intense and definite, while a neigh- 
bouring band is found to be forming, though more faintly, to the 
left of it, and separated from it by an interval of clear green light 
that had previously been obscured. 
6. Acid-Hcematoporphyrin . — To 100 c.c. of concentrated H 2 S0 4 
add in the cold 5 c.c. of fresh undiluted defibrinated blood. 
This can only be done in a glass vessel, and the liquids must be 
gently stirred to prevent any turbidity arising either from the 
FeS0 4 or from particles of carbon if some of the blood becomes 
charred. If specks of carbon do appear, the whole must be filtered 
through asbestos ; and if too dark to yield the spectrum, must be 
Ailuted only by the addition of concentrated H 2 S0 4 ; water must 
on no account be used. This iron-free pigment is very stable. It 
is somewhat interesting that treatment of blood with this strong 
acid develops the halitus sanguinis with considerable distinctness. 
