326 THE BLOOD. 



The reason of the slow coagulation of the blood in haemophilia is not 

 well known. Recent investigations of MORAWITZ and LOSSEN, SAHLI, 

 NOLF and HENRY 1 make it very probable that the thrombokinase plays 

 an important part. According to SAHLI the quantity of kinase is dimin- 

 ished, while according to NOLF and HENRY, it is qualitatively changed 

 so that it is less active. Both cases explain the repeatedly observed 

 relation of the vessel-walls to haemophilia ' as, according to NOLF, the 

 thrombokinase (his thrombozym) is also secreted by the endothelial cells. 



The non-coagulability of cadaver blood depends usually, according to MORA- 

 WITZ, 2 'upon tne fact that it contains no fibrinogen, due to a fibrinolysis. 



The gases of the blood will be treated in Chapter XVI (on respiration) 



IV. THE QUANTITATIVE COMPOSITION OF THE BLOOD. 



The quantitative analyses of the blood are of little value. We must 

 ascertain on one side the relation of the plasma and blood-corpuscles to 

 each other, and on the other the constitution of each of these two chief 

 constituents. The difficulties which stand in the way of such a task, 

 especially in regard to the living, non-coagulated blood, have not been 

 removed. Since the constitution of the blood may differ not only in 

 different vascular regions, but also in the same region under different 

 circumstances, which renders a number of blood analyses necessary, it 

 can hardly appear remarkable that our knowledge of the constitution of 

 the blood is still relatively limited. 



The relative volume of blood-corpuscles and serum in blood has been 

 determined by various methods. Of these methods that of L. and M. 

 BLEiBTREU, 3 against which important objections have been raised by 

 several investigators, such as EYKMAN, BIERNACKI and HEDiN, 4 must 

 be especially mentioned. In regard to this as well as to the method 

 of St. BUGARSKY and TANGL, which is based upon a difference in the 

 electrical conductivity of the blood and the plasma, and STEWART^ 

 colorimetric method, we must refer to the original publications. 



For clinical purposes the relative volume of corpuscles in the blood 

 may be determined by the use of a small centrifuge called a hcematocrit, 

 constructed by BLIX and described and tested by HEDIN. A measured 

 quantity of blood is mixed with a known volume (best an equal volume) 



1 Morawitz and Lessen, Deutsch. Arch. f. klin. Med., 94; Sahli, ibid., 99; Nolf 

 and Henry, Revue de medicine, 29, 1909. 



2 Hofmeister's Beitrage, 8. 



3 Pfliiger's Arch., 51, 55, and 60. 



4 Biernacki, Zeitschr. f. physiol. Chem., 19; Eykman, Pfluger's Arch., 60; Hedin, 

 ibid., and Skand. Arch. f. Physiol., 5. 



6 Bugarsky and Tangl, Centralbl. f. Physiol., 11; Stewart, Journ. of Physiol., 24. 



