100 PHYSIOLOGICAL CHEMISTRY. 



investigations of FERNET; but the quantity of these salts in the 

 serum is, at least in certain kinds of blood, for example in ox- 

 serum, so small that it can hardly be of importance. In regard to 

 the globulins SETSCHENOW is of the opinion that they do not act 

 as acids themselves, but form a combination with carbon dioxide, 

 producing carboglobulinic acid which unites with the alkali. Ac- 

 cording to SERTOLI, whose views have lately found a supporter in 

 TORUP, the globulins themselves are the acids combined with the 

 alkali of the blood-serum. In both cases the globulin would 

 form, directly or indirectly, that chief constituent of the plasma or 

 of the blood-serum which, according to the law of the action of 

 masses, contends with the carbon dioxide for the alkalies. By a 

 greater partial pressure of the carbon dioxide the latter deprives 

 the globulin alkali of a part of its alkali, and bicarbonate is formed ; 

 by low partial pressure the carbon dioxide escapes, and the bicar- 

 bonate is taken up by the globulin alkali. 



In the above statements it has been emphasized that the oxygen 

 in the blood occurs in a dissociable combination with the haemo- 

 globin, and for the formation of this combination, the oxyhsemo- 

 globin, a certain partial pressure of the oxygen is necessary at any 

 temperature. Also the carbon dioxide of the blood, that which is 

 contained in the blood- corpuscles as well as that in the plasma, oc- 

 curs mostly in combinations which are dependent to a great extent 

 upon the partial pressure of the carbon dioxide. For the study of 

 the exchange of gases between the blood and the alveolar air on 

 one side, and the blood and the tissues on the other, special regard 

 must be paid to the question as to how far this exchange of gases 

 is the result of the law of diffusion and how far other forces take 

 part in it; also the tension of the oxygen and the carbon dioxide 

 is of the greatest importance. 



The law of the dissociation of oxyhaemoglobin has been studied 

 by many investigators. Of the greatest physiological interest are 

 those investigations which relate to the dissociation at the temper- 

 ature of the body. In regard to these, many investigators (P. BERT, 

 HERTER, and HUFNER) have found, partly by experiments on the 

 living animal and partly by experiments with blood or pure haemo- 

 globin solutions, that the tension of the oxygen of the blood at the 

 temperature of the body corresponds to an oxygen partial pressure 



