VISCOSITY OF BLOOD 321 



TABLE XLIII 



Serum + X Corpuscles 



„ + 3-2 X 10" 

 „ + 6-3 X 10« 

 „ + 12-6 X 10« 



Viscosity at 32° C. 



1-9 



3-3 



4-9 



15-6 



The last high value was due to the mechanical blocking of the 

 capillary tube by the corpuscles which tend to agglutinate when 

 so concentrated. 



The capsule and its contents are colloidal in character. Acids 

 increase the power of colloids to imbibe water, and, therefore, one 

 would expect that COg would cause an increased imbibition of 

 water by the corpuscles and, consequently, increase the viscosity 

 of blood, due (a) principally to the absorption of water from the 

 plasma rendering it more viscous and (b) the swelling of the 

 corpuscle itself. The experimental proof of this has not been very 

 satisfactory, but some workers have observed increased viscosity 

 in venous blood, especially in cases where the unsaturation of 

 haemoglobin is low (pneumonia, gas poisoning). 



Viscosimetric measurements afford another means of determining 

 the volume of blood corpuscles. Viscosity depends principally on 

 the total volume of corpuscles per unit volume of fluid. Having 

 determined (i.) the viscosity of whole blood = pc, and (ii.) that of 

 the plasma = p, the total corpuscular volume K may be derived 

 from the fornuda 



1 ^ K = ^. 



pc 



If the total number of corpuscles per unit volume be A^ then 

 the average volume of each will be KjN . 



The results obtained from such an indirect method are fairly 

 regular, but cannot be considered as absolutely accurate, as 

 viscosity does not depend, in principle, on either the number or 

 the volume of corpuscles, but on the effective surface, i.e. on the 

 area liable to friction (see relation between viscosity and blood- 

 pressure). 



Further Reading 

 Ponder. '" The Erythrocyte and the Action of Simple Haemolysins." 

 Oliver and Boyd. 



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