298 THE BLOOD. 



(BRANDENBURG). The readily as well as the difficultly diffusible alkali 

 is divided between the blood-corpuscles and plasma, and the blood-cor- 

 puscles seem to be richer in difficultly diffusible alkali than the plasma or 

 serum. This division may be changed by the influence of even very 

 small amounts of acid, even of carbonic acid, and also, as shown by ZUNTZ, 

 LoEWYand ZUNTZ, HAMBURGER, LIMBECK, and GURBER/ by the influence 

 of the respiratory exchange of gas. The blood-corpuscles give up a part 

 of the alkali united with protein to the serum by the action of carbon 

 dioxide, hence the serum becomes more alkaline. The equilibrium of 

 the osmotic tension in the blood-corpuscles and in the serum is thus 

 disturbed; the blood-corpuscles swell up because they take up water 

 from the serum, and this then becomes more concentrated and richer 

 in alkali, protein, and sugar. Under the influence of oxygen, the cor- 

 puscles take their original form again and the above changes are reversed. 

 The blood-corpuscles for this reason are less biconcave in their small 

 diameter in venous than in arterial blood (HAMBURGER) . 



These conditions have been further studied by v. KORANYI and 

 BENCE, 2 and they have investigated the relation between the changes of 

 the volume of the blood-corpuscles and the electrical conductivity, the 

 refractivity of the serum and the viscosit}^ of the blood. The refrac- 

 tion coefficient of the serum is highest with an increase in the amount of 

 carbon dioxide, while it is lowest when the blood is rich in oxygen and 

 poor in carbon dioxide. They consider this as an action of acid, as a 

 similar rise is observed after the addition of acid, while after the addition 

 of alkali a fall in the refraction cofficient of the serum takes place, and 

 these same changes can be brought about by CO 2 or by a current of oxygen. 

 With an increase in the amount of carbon dioxide, the conductivity of 

 the blood diminishes; the viscosity is, on the other hand, highest when 

 the blood is richest in carbon dioxide. If the CO 2 is driven off by O 

 the viscosity diminishes to a minimum, and on leading in more oxygen 

 it rises again. The changes in viscosity 2 of the blood runs parallel with the 

 volume changes of the blood-corpuscles, and changes in the viscosity, which 

 can be brought about by the removal of carbon dioxide, cause a change 

 in the electric charge of the blood-corpuscles (v. KORANYI and BENCE). 



The color of the blood is red light scarlet-red in the arteries and dark 

 bluish red in the veins. Blood free from oxygen is dichroic, dark red 

 by reflected light and green by transmitted light. The blood-coloring 



1 Zuntz, in Hermann's Handbuch der Physiol., 4, Abt. 2; Loewy and Zuntz, 

 Pfluger's Arch., 58; Hamburger, Arch. f. (Anat. u.) Physiol., 1894 and 1898, and 

 Zeitschr. f. Biologic, 28 and 35; v. Limbeck, Arch. f. exp. Path. u. Pharm., 35; Giirber, 

 Sitzungsber. d. phys. med. Gesellsch zu Wiirzburg, 1895. 



2 Pfluger's Arch., 110. 



3 In regard to the viscosity of the blood and the literature of the subject, see R. 

 Hober in Oppenheimer's Handb. der Bioch., 2, p. 12-18 



