Full resolution (JPEG) - On this page / på denna sida - V. The Blood - II. The Form-elements of the Blood - Blood-pigments
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
METHEMOGLOBIN. 283
crystals are as a rule isomorphous with the corresponding oxyhemo-
globin crystals, but are darker, having a shade toward blue or purple,
and are decidedly more pleochromatic. The haemoglobin from horse-
blood has also been obtained by Uhlik x
in hexagonal plates. Its
solutions in water are darker and more violet or purplish than solu-
tions of oxyhemoglobin of the same concentration. They absorb the
blue and the violet rays of the spectrum in a less marked degree, but
strongly absorb the rays lying between C and D. In proper dilution
the solution shows a spectrum with one broad, not sharply defined band
between D and E, whose darkest part corresponds to the wave-length
X = 559 (spectrum Plate, 2). This band does not lie in the middle
between D and E, but is toward the red end of the spectrum, a little
over the line D. This pigment also gives a band in the ultra-violet,
X = 429. A haemoglobin solution actively absorbs oxygen from the air
and is converted into an oxyhemoglobin solution.
A solution of oxyhemoglobin may be easily converted into a solution
having the spectrum of hemoglobin by means of a vacuum, by passing
an indifferent gas through it, or by the addition of a reducing substance,
as, for example, an ammoniacal ferrous-tartrate solution (Stokes’ reduc-
tion liquid). If an oxyhemoglobin solution or arterial blood is kept in
a sealed tube, we observe a gradual consumption of oxygen and a reduc-
tion of the oxyhemoglobin into hemoglobin. If the solution has a
proper concentration, a crystallization of hemoglobin may occur in the
tube at lower temperatures (Hufner 2
).
Methaemoglobin. This name has been given to a coloring-matter
which is easily obtained from oxyhemoglobin as a transformation prod-
uct and which has been correspondingly found in transudates and cystic
fluids containing blood, in urine in hematuria or hemoglobinuria, and
also in urine and blood on poisoning with potassium chlorate, amyl
nitrite or alkali nitrite, and many other bodies.
Methemoglobin does not contain any oxygen in molecular or dis-
sociable combination, but still the oxygen seems to be of importance in
the formation of methemoglobin, because it is formed from oxyhemo-
globin and not from hemoglobin in the absence of oxygen or oxidizing
agents. If arterial blood be sealed up in a tube, it gradually consumes
its oxygen and becomes venous, and by this absorption of oxygen a little
methemoglobin is formed. The same occurs on the addition of a small
quantity of acid to the blood. By the spontaneous decomposition
of blood some methemoglobin is formed, and by the action of ozone,
potassium permanganate, potassium ferricyanide, chlorates, nitrites,
1
Pfluger’s Arch., 104.
2
Zeitschr. f. physiol. Chem., 4; see also Uhlik, 1. c.
<< prev. page << föreg. sida << >> nästa sida >> next page >>
