852 RESPIRATION AND OXIDATION. 



Oxygen is dissolved only in a small extent by the plasma, whose 

 absorbability for oxygen is 97.5 per cent of that of water, according to 

 BOHR. The greater part or nearly all of the oxygen is loosely combined 

 with the haemoglobin. The quantity of the oxygen which is contained in 

 the blood of the dog corresponds closely to the quantity which, from the 

 activity of the haemoglobin, we should expect to combine with oxygen 

 and from the quantity of haemoglobin contained therein. It is difficult 

 to ascertain how far the circulating arterial blood is saturated with oxygen, 

 as immediately after bleeding a loss of oxygen always takes place. Still 

 it seems to be unquestionable that it is not quite completely saturated 

 with oxygen, in life. The laws which regulate the binding of the oxygen 

 in the blood will be found in the discussion of the gas exchanged between 

 the blood and the air of the lungs. 



The carbon dioxide of the blood occurs in part, and indeed, accord- 

 ing to the investigations of ALEX. SCHMIDT/ Zu-NTz-, 2 and L. FREDERICQ, S 

 to the extent of at least one-third in the blood-corpuscles, also in part, 

 and in fact the greatest part, in the plasma or serum. BoHR 4 claims 

 that about 30 mm. may be considered as the average pressure of the 

 carbon dioxide in the organism, and with such a pressure the quantity of 

 physically dissolved CO2 in 100 cc. of the blood amounts to 2.01 cc. As 

 the blood with this tension takes up about 40 vols. per cent C02, there- 

 fore about 5 per cent of the total carbon dioxide is simply dissolved. 

 Under the assumption that the blood corpuscles make up about one- 

 third of the volume of the blood, of the physically dissolved C02, 0.59 

 cc. exists with the corpuscles and 1.42 cc. with the plasma. 



As the blood corpuscles in 100 cc. blood as above stated take up at 

 the above pressure about 14 cc. CO2, only a small part of its CO2 is physi- 

 cally dissolved. The chief mass of the C02 is loosely combined and the 

 constituent of these cells which unites with the CCb seems to be the 

 alkali combined with phosphoric acid, oxyhaemoglobin or haemoglobin, 

 and globulin on one side and the haemoglobin itself on the other. That 

 in the red blood-corpuscles alkali phosphate occurs in such quantities 

 that it may be of importance in the combination with carbon dioxide 

 is not to be doubted; and it must be allowed that from the diphosphate, 

 by a greater partial pressure of the carbon dioxide, monophosphate and 

 alkali carbonate are formed, while by a lower partial pressure of the 

 carbon dioxide, the mass action of the phosphoric acid again comes into 

 play, so that, with the carbon dioxide becoming free, a reformation of 



1 Ber. d. k. sachs. Gesellsch. d. Wissensch. math.-phys. Klasse, 1867. 

 2 Centralbl. f. d. med. Wissensch., 1867, 529. 

 8 Recherches sur la constitution du Plasma sanguin, 1878, 50, 51. 

 4 In regard to the work of Bohr we will refer here and in future to Nagel's Handbuch 

 der Physiologie des Menschen, Bd. 1. 



