TRANSPORT OF CARBON-DIOXIDE 



255 



obvious that while these factors may almost be neglected in the 

 consideration of the transport of oxygen, they have to be reckoned 

 with in the case of carbon dioxide. 



TABLE XXXIX. 



PARTITION OP C0 2 IN 100 c.c. OP DEPJBRINATED BLOOD 

 (HAEMATOCRITE VALUE = 51). 



Vol. of CO 2 Vol. of CO., Vol. of CO, 



CO, tension. in blood. in serum. in corpuscles. 



Oxygenated - 40 45-0 25-9 19-1 



Keduced- 40 50-4 28-0 22-4 



That is, in arterial (whole) blood, there is about 50 c.c. of CO 2 , 

 of which amount the fibrinogen carries about 5 c.c., the serum 

 (proteins, water and crystalloid bases) about 26 c.c. and the 

 corpuscles about 19 c.c. 



TABLE XL. 

 100 c.c. OF ARTERIAL BLOOD (C0 2 tension 40 mm., 2 tension 100 mm.). 



CORPUSCLES \ ( in solution 0-85 c.c. 



51% by volume I carry -?- of total C0 2 bound (e.g. NaHC0 3 ) 8-45 c.c. 



' adsorbed by Hb, etc. 9-7 c.c. 



PLASMA 



49% by volume 



carries i of total CO.- 



19 c.c, 



in solution 1-2 c.c. 



bound (NaHC0 3 ) 23-8 c.c, 



adsorbed by fibrino- 

 gen - 5 c.c. 



adsorbed by serum 



proteins 1 c.c. 



31 c.c, 

 100 c.c. OF VENOUS BLOOD (C0 2 tension = 45 mm., 0, tension = 40 mm.). 



CORPUSCLES carry - 22 c.c. == + 3 c.c. 

 PLASMA carries 34 c.c. = + 3 c.c. 



56 c.c +6 c.c. 



For all practical purposes there is very little difference between 

 the corpuscles and plasma as transporters of carbon dioxide. 

 But, in times of stress when the CO 2 tension tends to be abnor- 

 mally high or when the desaturation of oxyhaemoglobin becomes 

 abnormally great (e.g. over 40 per cent.) the corpuscles will play 

 the major part in the transport of CO 2 . 



Plasma must be considered as a fluid separated from other 

 fluids (with which it is in equilibrium) by membranes permeable 

 to certain solutes. The whole transport system is a multi-phase 

 fluid in equilibrium. Alterations in any phase produce regulatory 



