310 COLLOIDS IN BIOLOGY AjVD MEDJCINE 



serum is able to take up more C0 2 than the blood corpuscles, but it is 

 impossible at present to formulate in detail the steps in the absorption 

 and release of C0 2 by the blood. The adsorption theory of Wo, 

 OSTWALD naturally does not help us over these difficulties, but under 

 the complicated conditions mentioned it formally establishes the 

 adsorption character of the absorption and release of C0 2 in the blood. 

 If we view teleologically the manner of gas exchange, we recog- 

 nize that adsorption serves this purpose best. Excess of oxygen 

 (up to 100 per cent) in the respired air has no effect either in the 

 used or on the general metabolism; when oxygen is deficient small 

 quantities are taken up with avidity and tenaciously held. The in- 

 halation of oxygen recently recommended for clinical use may be 

 explained only by considering the plasma. 1 From a mixture rich in 

 oxygen, hemoglobin will take up only a given maximum quantity, 

 but the ability of the plasma to take up oxygen follows the gas 

 pressure. Finally, it must be recalled that with higher pressure the 

 lipoids of the blood corpuscles take up more oxygen. [No discussion 

 of the gas exchange in the blood would be complete without mention 

 of the work of BARCROFT, ''Respiratory Function of the Blood," 

 Cambridge, 1914, and of HENDERSON, and of DONALD VAN SLYKE, 

 who have supplied methods and data of great value. Tr.] 



The Circulation and Its Disturbances. 



A normal circulation can exist only when the internal friction of 

 the blood, the viscosity, remains within normal limits. This varies 

 considerably, and in man, measured for uncoagulated blood, is from 

 4.05 to 6.8 (water = 1). In cardiac patients, besides normal values, 

 values from above 14 to 23.8 have been found. Muscular exercise, 

 heat and chemical stimuli influence the viscosity (H. A. DETER- 

 MANN *). Salivation, lack of water, perspiration increase, whereas 

 ingestion of fluids or nourishment as well as increased frequency 

 of respiration lower the viscosity (M. SCHEITLIN*). According to 

 H. BLUNSCHLY the viscosity of the blood falls with every intake of 

 nourishment, reaching a minimum after the midday meal, and then 

 rises with fluctuations. The differences in the same person on one 

 day were 11.8 per cent; yet the figures vary much on different days. 

 Moderate muscular work according to H. A. DETERMANN lowers 

 the viscosity of the blood, hard work raises it as do alcohol and 

 coffee. 



The viscosity of the blood may be influenced by certain substances; 

 according to W. SCHEITLIN,* a gelatin injection of 0.15 per cent of the 

 1 Naturally this does hold in the case of CO poisoning. 



