( 618 ) 
does not proceed from the fibrinogen, but that this proteid was 
already present in the fibrinogensolution, for it could not be explained, 
that on one hand, the fibrinogen precipitated with Na Fl produces 
no or but little fibringlobulin, and that on the other hand the liquid 
filtered off from this precipitate contains fibringlobulin in such greater 
quantity. 
It here is necessary to discuss still a few objections that might be 
raised against this conclusion. 
Firstly — on account of the fact that the fibrinogen precipitated 
with Nakl, dissolves with more difficulty in diluted saltsolution than 
the usual fibrinogen, and that the solution does not produce any 
fibringlobulin by heating — it might be asked whether the substance 
precipitated with NaF l might not be a kind of soluble fibrin, as for 
instance the “fibrine conerete pure” described by Denis. The latter 
also principally dissolved in diluted saltsolution at 40°; while the 
dissolution went very slowly at the temperature of the room. Against 
the opinion that the substance precipitated with NaFl is a soluble 
fibrin speaks first the coagulation temperature which was found by 
Denis for the dissolved “fibrine conerète pure” at 60—65°, while in 
every case it is not higher than 55° for the substance precipitated 
with Nak]. The strongest argument against the opinion that this last 
is fibrin, namely the power of this substance to clot with fibrinferment, 
I have already stated several times; if we further take into consider- 
ation that the fibrinogen prepared with Nall behaves with respect 
to acetic acid, half saturation with salt ete. quite as common fibri- 
nogen, the opinion that this substance is fibrin may be considered 
as having been refuted. 
As to the slight solubility of the fibrinogen precipitated with NaF] 
and in diluted salt solution, this peculiarity may be explained in 
this way, that on being heated with NaFl it forms a slight soluble 
fluorine-compound of the fibrinogen, which dissolves only very slowly 
in saltsolution; by the great abundance of chlorine-ions then present, 
this dissolving will probably be accompanied by an exchange of the 
fluorine by chlorine. It is still rendered more probable that a fluorine- 
compound is formed, when we consider that the slight quantity of the 
natrium fluoride solution cannot be put on one line with the precipitating 
of proteid by the saturating of the solution with a neutral salt. 
It might be imagined that the fibrinogen, it is true, is precipitated 
as such by natrium fluoride, but that also (especially as natrium fluoride 
solutions usually react slightly alkaline) part of the fibrinogen is 
changed into fibringlobulin; by which the presence of fibringlobulin 
in the filtrate would be explained. 
