Outlines of practical physiology : being a manual for the physiological laboratory, including chemical and experimental physiology, with reference to practical medicine / by William Stirling.

  • William Stirling
Date:
1902
Catalogue details

Licence: Public Domain Mark

Credit: Outlines of practical physiology : being a manual for the physiological laboratory, including chemical and experimental physiology, with reference to practical medicine / by William Stirling. Source: Wellcome Collection.

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    spectrum is shortened by absorption (fig. 19, 2). On further dilution /3 disappears first, about o4oi p.c. If a has disap¬ peared, the p.c. is less than 01 of Hb. [The mid line of a cor¬ responds to W.L. or X 578, that of /3 about 540 (fig. 34).] Using coloured chalks or 'pencils, sketch the appearances seen with each dilution, and indicate opposite each the degree of the latter. [Prof. Engelmann has recently published coloured spectral charts which are very serviceable.] (e) Make a solution of blood, showing one undivided band; add water, so that it mixes but slightly with the upper strata of the blood. The same result is obtained by using a wedge- shaped bottle for the blood solution. Move the tube so as to examine first the deeper strata until the surface is reached. At first a single band ; but as the solution is more dilute above, two Fig. 20. — Graphic representation of the absorption of light in a spectrum by solutions of oxy-haemoglobin, of differ¬ ent strengths. The shading indicates the amount of absorption of the spec¬ trum, and the numbers at the side the strength of the solution. Fig. 21.—Graphic representation of the absorption of light in a spectrum by solutions of reduced Hb, of dif¬ ferent strengths. The shading indi¬ cates the amount of absorption of the spectrum, and the numbers at the side the strength of the solution. bands begin to appear, and as the solution is weaker above, /3-band disappears, until, finally, with a very weak solution, such as is obtained in the upper strata only, the a-band alone is visible. Fig. 20 shows the amount of light absorbed by solu¬ tions of HbO., (1 cm. in thickness) and of various strengths. (f) Gradually increase the strength of the solution, and observe how more and more of the spectrum is cut off, both at the red and blue ends, but especially at the latter. The two bands run together to form one con¬ tinuous broad band—light now only passes through red and green. If made stronger the green is cut out, and only red passes. {g) Hold up the hand before a strong light with the fingers erect and