172 THE BLOOD. 



drawal from the body in larger amount. It is noteworthy in this connection 

 that certain forms of lymph, such as the aqueous humour, which contain no 

 cells, contain also no nucleo-proteid, and are only coagulable on the addition of 

 nucleo-proteid. 



Theory of Lilienfeld. Lilienfeld, 1 like Arthus and Pekelharing, con- 

 siders that fibrin is formed by a combination of fibrinogen with lime, any 

 soluble lime salt being equally effectual to produce the combination. 

 Lilienfeld differs, however, from them in denying the necessity for the 

 intervention of a ferment in the ordinary sense of the word. He considers 

 that what the nucleo-proteid effects is not the combination of nbrinogen 

 with lime, but a transformation or splitting of the nbrinogen into a sub- 

 stance which he terms " thrombosin," Slid a globulin ; the throuibosin then 

 combines with lime, if any be present, to form fibrin. The nucleo-proteid 

 only acts, according to Lilienfeld, by reason of the acid qualities of the 

 nucleic acid it contains. Any other weak acid, e.g. acetic, will answer 

 equally well. Thus, if a solution of nbrinogen in NaCl (prepared 

 according to Hammarsten's method) is precipitated by acetic acid, the 

 precipitate (thrombosin), if dissolved in weak sodium carbonate, instantly 

 forms a coagulum (fibrin), on the addition of calcium chloride. The 

 formation of the thrombosin by the action of an acid upon fibrinogen 

 is, according to Lilienfeld, a precursor to the production of fibrin, and 

 is analogous to the change in caseinogen by the action of rennin, which 

 will occur in the absence of lime salts, although the latter are necessary 

 for the formation of the casein clot (see p. 135). 



I have elsewhere shown ' 2 that this theory is untenable ; for a solution 

 of fibrinogen in dilute salt solution, prepared by Hammarsten's method, 

 will, if sufficiently strong, coagulate, on the addition of calcium chloride, 

 equally well with a solution of the acetic acid precipitate the so-called 

 thrombosin although somewhat less rapidly. 3 The difference in rapidity 

 depends, no doubt, upon the fact that sodium chloride in a certain 

 amount retards the formation of the clot, or even may prevent it 

 altogether. This, as Hammarsten has pointed out, is the reason why 

 Lilienfeld obtained no coagulum on the addition of calcium chloride 

 to his fibrinogen solution, although he got a coagulum with his 

 so-called thrombosin solution, for the former was dissolved by aid 

 of sodium chloride, and the latter by dilute alkali. As already 

 stated, 4 Hammarsten holds that in neither case is the coagulum pro- 

 duced a true fibrin, but in both cases it is a fibrin-like combination 

 of fibrinogen with lime. The influence of nucleo-proteid is, however, 

 not eliminated, 5 for, as has been already insisted on, fibrinogen pre- 

 pared by Hammarsten's method always contains some nucleo-proteid. 

 This is clear both from my own experiments and from the analyses 

 of Lilienfeld, who indeed but as it would appear without sufficient 

 cause supposes fibrinogen itself to be a nucleo-proteid. The amount 

 of nuclein or phosphorus which can be obtained from it certainly does 

 not warrant the assumption ; nevertheless there is always a distinct 



1 Ztschr. f. physiol. Chem., Strasslmrg, 1895, Bd. xx. 



2 Proc. Physiol. Soc., Journ. Physiol. , Cambridge and London, 1895, vol. xvii. 

 p. xviii. 



3 Cf. Cramer, Ztschr. f. physiol. Chem., Strassburg, 1897, Bd. xxiii. S. 74, who has 

 fully confirmed the conclusion that the so-called " thrombosin " is merely fibrinogen. 



4 See note 5, p. 165. 



5 Cf. Wistinghausen, Diss., Dorpat, 1894. 



