CHAP. II.] THE BLOOD. 51 



The Researches of Hammarsten 1 . 



In describing paraglobulin and fibrinogen it has been stated that 

 the researches of Eichwald and Hammarsten, and especially of the 

 latter, have shewn that the behaviour of the two bodies which, according 

 to Schmidt, are the fibrin-factors, in respect to sodium chloride is 

 exceedingly diverse. Both bodies are precipitated from their solutions 

 when these are saturated with sodium chloride, though fibrinogen 

 alone is completely precipitated. Fibrinogen is precipitated from its 

 solutions when these contain 13 p. c, of sodium chloride or more, 

 whilst paraglobulin only becomes insoluble when the solution contains 

 about 20 p. c. or more of sodium chloride. 



Making use of these reactions and following the method which 

 has been described when speaking of fibrinogen, Hammarsten has 

 separated fibrinogen which is free from all traces of serum-albumin and 

 of paraglobulin, and has found that such fibrinogen dissolved in weak 

 solutions of sodium chloride may be kept indefinitely without under- 

 going coagulation. When, however, there is added to it serum of 

 blood, or a solution of fibrin-firment prepared according to the 

 directions of Schmidt or by improved methods, coagulation occurs 

 with great rapidity. 



Fibrinogen According to Hammarsten, then, the coagulation of 



the one pre- the blood depends upon the production of fibrin from 

 cursor of one body, fibrinogen, existing in solution in the liqu'or 



sanguinis, under the influence of that yet non-isolated 

 body, the fibrin-ferment. Although provisionally em- 

 ploying the term fibrin- ferment, Hammarsten, like Schmidt, does not 

 commit himself to the view that this body is really of the nature of a 

 ferment. 



The grounds upon which Hammarsten has corne to the conclu- 

 sion that paraglobulin is not indispensable to the formation of fibrin 

 are the following : 1st. The fibrinoplastic action is not a specific 

 property of paraglobulin, but is 'exerted by some other substances, 

 such as calcium chloride and impure casein. 2nd. The fibrinoplastic 

 activity does not belong to pure paraglobulin, but only to that 

 substance when precipitated from serum and certain other fluids. 

 In accordance with this statement Hammarsten has obtained from 

 hydrocele fluids, which were quite free from ferment, a pure para- 

 globulin, which possessed all the typical properties of that body, but 

 exerted no fibrinoplastic activity. 3rd. The chief proof in support 

 of Schmidt's hypothesis is based upon the surmise that those 

 hydrocele fluids which do not coagulate when treated with ferment 

 alone, but only after the addition of paraglobulin, either do not 



1 Hammarsten : " Untersucliungen iiber die Faserstoffgerinmmg." Nov. Acta Reg. 

 Soc. Scientiar. UpsaL, Ser. x. Vol. x. Separatabdruck, Upsala, 1878." Zur Lehre von 

 der Faserstoffgerinnung." Pfliiger's Archiv, Vol. xiv. (1877) pp. 211 274. "Ueber das 

 Paraglobulin." PflUger's Archie, Vol. xvn. pp. 413 468. "Ueber das Paraglobuliu, 

 zweiter Abschnitt." Pfliiger's Archiv, Vol. xvm. pp. 38116. "Ueber das Fibrinogen. 

 Pniiger?s Archiv, Vol. xix. pp. 563622. 



42 



