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COAGULATION OF THE BLOOD. 321
and these have also, although only in the presence of lime salts (if the author
understands Loeb), a direct coagulating action upon fibrinogen. According to
Loeb the tissue coagulina do not act as kinases in the invertebrates, and he also
finds it improbable that they would act as kinases in the vertebrates. Under
favorable conditions the combined blood and tissue coagulins are more active
than the Bum of the individual action. That this is due to an activation by a
kinase, which is a possible explanation, has, in Loeb’s opinion, not been proved.
The coagulins of the blood are, as above stated, according to Loeb, different
from the tissue coagulins. The latter are for different classes of animals so
adapted that they bring about a quicker coagulation in the blood of certain classes
of animals than do the other class. The erythrocytes of mammalia (cat, dog, ral )1 tit
)
contain, on the contrary, according to Loeb and Fleisher ’
coagulins of such a
specific adaptability that it is possible to differentiate between the blood corpuscles
of different kinds of mammalia or, if the erythrocytes are known, to detect an
unknown plasma.
Opinions are strikingly at variance in regard to the mode cf action
of the tissue constituents which accelerate coagulation, and their nature
also is entirely unknown, hence great confusion exists on the whole in
this subject.
If we accept the fact that thrombokinase does not occur in the plasma,
but is produced under the influence of a foreign body acting as an excitant,
it is rather difficult to understand why the plasma obtained from blood
collected in a paraffined vessel and quickly and strongly centrifuged,
and which is perfectly free from form-elements, should remain fluid for
a long time in a paraffined vessel while it coagulates in an ordinary glass
vessel. Nolf has tried by his theory to explain this difficulty, as well
as the action of the alcohol-soluble zymoplastic substances (Alex.
Schmidt).
According to Nolf 2
the following bodies take direct part in the
coagulation of the blood, namely: Fibrinogen, thrombogen (formerly
called hepatothrombin by him) thrombozym ( = thrombokinase of Mora-
witz) and lime salts. The coagulation of the blood, according to him,
is a different process from the coagulation of a fibrinogen solution by
thrombin. While in this last case the thrombin is the substance exciting
coagulation, in the other case the thrombin is a product of the coagu-
lation, as suggested by Wooldridge. In the coagulation of the plasma,
according to Nolf we have a mutual precipitation of the three above-
mentioned colloids—fibrinogen, thrombogen and thrombozym, all three
of wliich are contained in the fibrin clot. This latter has correspondingly
no constant composition, but varies according to the relative propor-
tions of these three colloids. In the presence of only a little fibrinogen
thrombin is produced from the three colloids (in the presence of lime
salts) ; in the presence of abundance of fibrinogen, on the contrary, fibrin
1
Loeb and Fleisher, Bioch. Zeitchr. 28.
2
Arch, internat. de Physiol., 6, Fasc, 1, 2, and 3 and 7 and 9.
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