1 72 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 fibrinogen 
with lime, but a transformation or splitting of the fibrinogen into a sub- 
stance which he terms " thrombosin," and a globulin ; the thrombosin 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 fibrinogen 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 reniiin, winch 
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., Strasstuirg, 1895, Bd. xx. 
- Proc. Physiol. Soc, Journ. Physiol., Cambridge and London, 189f>, 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. Wistiughausen, Diss., Dorpat, 1894. 
