BLOOD, RESPIRATION, CIRCULATION AND DISTURBANCES 311 



blood volume increases the viscosity temporarily 15 per cent; are- 

 colin (0.1 grm., subcutaneously) up to 36 per cent; cutaneous appli- 

 cation of spiritus sinapis, up to 12 per cent; a phlebotomy (up to 

 12 per cent) and the action of other derivatives, for a few hours 

 lower the viscosity (these results were obtained on horses). Changes 

 in viscosity were observed by W. SCHEITLIN in various diseases 

 (principally of horses) ; and by W. FREI * on dying horses. In dis- 

 eases of the lungs and pleura associated with fever, especially high 

 values were found, and in anemias they were especially low (as low 

 as 2.3). The viscosity usually reaches its highest point with the 

 crisis and then falls. 



AH these observations furnish valuable material for future knowl- 

 edge of the relationship between the viscosity of the blood and 

 pathology. Already it may be said that the viscosity of the blood 

 has a certain prognostic value. 



The viscosity of the blood is conditioned by the internal friction 

 of the plasma and by the blood cells. We shall see later that the 

 total amount of the former plays a far less important part than 

 the latter, and that, as a matter of fact, an important part in the 

 changes in viscosity of the plasma must also be ascribed to the 

 interface tissue/plasma. 



Marked changes in the viscosity of the plasma may also be indu ced 

 by the inclusion of some foreign substances. P. ADAM found that it 

 is lowered markedly by iodids, and to a less extent by bromids. 

 It is possible that some of the therapeutic effects from the adminis- 

 tration of potassium iodid (especially in arteriosclerosis) may be 

 attributed to the diminution of the internal friction. Investigations 

 on man have not as yet given uniform results (P. ADAM, H. A. 

 DETERMANN,* MULLER and R. INADA). 



The concentrations of urea possible in the organism can have no 

 influence on the internal friction of the plasma (as far as I can gather 

 from G. MORUZZI'S* figures). 



To the extent that the data furnished by Wo. PAULI and H. 

 HANDOVSKY warrant it, an increased ionization of the serum albumin 

 must also result in an increase of viscosity. Such an increased 

 ionization of albumin may be brought about by an increase in con- 

 centration of H or OH ions. An increase of the latter is impossible, 

 as we shall see. On the other hand, the following tables of R. HOBER 

 show that an increase of C0 2 may produce an increase of the con- 

 centration of H ions in the blood. 



R. HOBER * 2 measured the concentration of H ions hi the blood 

 upon the addition of carbonic acid mixed with hydrogen. I have 

 reproduced only the percentage of C0 2 . 



