THROMBOSIS 269 



ment varies directly with the number of leucocytes in the blood. 

 Kollmann l found an increase in the fibrin in eclampsia, which 

 Lewinski 2 could not substantiate. In experimental infections 

 of animals Langstein and Mayer 3 found a specific increase in 

 pneumococcus sepsis, which undoubtedly bears an important 

 relation both to the characteristic fibrinous nature of the alveo- 

 lar exudate in pneumonia, and the striking amount of fibrin found 

 in pneumococcus pleuritis, peritonitis, etc. Mathews 4 found an 

 increase in the fibrin with all experimental suppurations. 



The coagulation time of the blood may be determined 

 experimentally by methods devised by Vierordt, 5 A. E. Wright , 6 

 and by Brodie and Russell, 7 the last named being considered the 

 best by Murphy and Gould. 8 The average time of coagulation 

 is between three and six minutes. In jaundice a delayed 

 coagulation time has generally been observed, but was not con- 

 stantly found by Murphy and Gould. 



THE FORMATION OF THROMBI 



If we apply the facts brought out in the preceding discussion 

 relative to the factors in the coagulation of blood, to the man- 

 ner and conditions under which thrombi are formed in the 

 circulating blood, we find explanations for many of the 

 features of thrombosis. Welch 9 describes the steps in the 

 formation of a thrombus after injury to the vessel-wall, as fol- 

 lows : First, there is an accumulation of blood-platelets adher- 

 ing to the wall at the point of injury. Leucocytes, which may 

 be present in small numbers at the beginning, rapidly increase 

 in number, collecting at the margins of the platelet masses and 

 between them. Not until the leucocytes have accumulated 

 does the fibrin appear. As Welch remarks, these findings 

 afford no conclusive evidence as to whether fibrin-ferment is 

 formed from the leucocytes or from the platelets, but since the 

 fibrin does not appear until after the leucocytes have accumulated, 

 and also since small thrombi may consist solely of platelets with- 

 out fibrin, it seems probable that the leucocytes must be looked 

 upon as the chief source of the ferment. Sometimes small clots 

 may form without the apparent participation of either platelets 

 or leucocytes. These purely fibrinous thrombi seem to start from 



1 Cent. f. Gynak., 1897 (21), 341. 2 Pfliiger's Arch., 1903 (100), 611. 



3 Hofmeister's Beitr., 1903 (5), 69. 4 Amer. Jour. Physiol., 1899 (3), 53. 

 5 Arch. f. Heilk., 1878 (19), 193. 6 Brit. Med. Jour., 1894 (i), 237. 



7 Jour, of Physiol., 1897 (21), 403. 



8 Boston Med. and Surg. Jour., 1904 (151), 45. 



9 Albutt System, vol. 6, complete discussion of the general features of 

 thrombosis; also see Jores, Ergebnisse der Pathol., 1988 (5), 1. 



