Volume 1

A text-book of human physiology : including histology and microscopical anatomy : with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition, with additions, by William Stirling.

Date:: 1891

Credit: A text-book of human physiology : including histology and microscopical anatomy : with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition, with additions, by William Stirling. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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$absorption-band, is formed. The colour changes from a bright red to a purplisl. or claret tint The two hands arc reproduced by shaking the reduced hsemoglobin with'air whereby HbO„ is again formed. Solutions of oxyluemoglobin arc rcaddy distimni’ished by their scarlet colour from the purplish tint of reduced Inemoglobin. IThe single absorption-band (fig. 23, 4), designated by the letter (y), lying aliout midway between the position of the two ]ircvious bands, is broader, fainter, less nCB V i,CB D Eh Figs. 24 aiul 2.a. Fig. 24, graphic repre.sentatioii of the spectrum of HbO^. Fig 25, the same of Hb, ‘he amount of absorption with varying strengths of hremoglobin, the thickness of the flu remaining the same. The numbers indicate the percentage of colouring matter. deeply shaded, and its centre is about, but not quite, intermediate between _D and E It extends between the wave-lengths 595 and 538, and is blackest opposite the wave-length 550, so that it lies nearer D than E. At the same time more of the blue rays are transmitted. On dilution the band is not resolved into two, but simply becomes fainter and disappears.] fAccording to Hermann, the absorption-band of Hb is not a single band, there being in addition a very narrow band towards the red end of the spectrum, but separate from the c iie absorption-band by a very small interval.] [Hamioglobin has certain remarkable characters :—(1) Although it is a crystalloid body it diffuses with difficidty through an animal membrane, owing to the large size of its molecule. (2) It readily combines with 0 to form an unstable and loose chemical compound, oxylisenioglobin. (3) This 0 it gives up readily to the tissues or other deoxidising reagents. (4) Its composition is very complex, for, in addition to the ordinary elements present in proteids, it contains a remarkable amount of iron (0'4 per cent).] If a string be tied round the base of two fingers so as to interrupt the circuMiou, spectro- scopic examination shows that the oxyha?moglobin rapidly passes into reduced Hb {yicrorcU). Cold delays this reduction ; it is accelerated in youth, during muscular activity, or by suppiessea respiration, and usually also during fever. ■ • „..f The spectroscopic examination of small blood-stains is often of the utmost forensic import- ance. A minimal drop is sufficient. Dissolve the stain in a few drops of distilled v;ater, ant iilace the solution in a thin glass tube in front of the slit of the speetroscope. Para-hjemoglobin.—If HbO.j be preserved under alcohol it passes into a modified torm, which is insoluble in water (NeneJd and Sicher). 2. MethsBmoglobin i.s a more stalile, cry.stalliiie compound {Hop2}e-Se!jler). It contain.s the .same amount of 0 as IIbO.2, but in a different chemical union, 1111110 the 0 is also more firmly united with it. It shows four absorption-bands like haematin in acid solution (fig. 23, 5), of which that between C and D is distinct, the second is very indistinct, while the third and fourth readily fuse, so that these last two bands are only well seen with good apparatus. It is produced spontaneously in old brown blood-stains, in the crusts of bloody uounds, in cysts with sanguinoleiit contents, and in bloody urine. Chemically, it can be picpaiei i$