BLOOD-CORPUSCLES AND GASES. VISCOSITY. 311 



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 equilib- 

 rium 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. KORAN YI and 

 BENCE/ 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 viscosity 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 coefficient of the serum takes place, and 

 these same changes can be brought about by C(>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 CO2 is driven off 

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

 oxygen it rises again. The changes in viscosity 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 viscosity of the blood is a variable quantity which, 

 besides the gas content of the blood, is also dependent upon many other 

 circumstances (ADAM 2 ) and which is different at various ages and under 

 unequal physiological and pathological conditions. 



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 

 matters occur in the blood-corpuscles. For this reason blood is opaque 



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

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

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



1 Pfluger's Arch., 110. 



2 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. See also Adam, Zeitschr. 

 f. klin. Med., 68. 



