70 SCIENCE PROGRESS 
albumose, is the type—which exert specific action only when they 
are introduced into the circulating blood. The reaction of the 
organism, consequent upon intravenous injection, is essential, 
in order that substances restraining coagulation shall arise. 
2. Substances which act independently and directly upon 
blood both inside and outside the organism. 
Various animals react differently to peptone injection, and 
individuals of the same species require various amounts of 
peptone per kilogramme body-weight. To obtain blood which, 
when shed, shall be completely incoagulable, the injection must 
be made into the circulation with rapidity, and the animals 
should be fasting. Contejean states that when peptone is 
introduced into the peritoneal cavity it has no effect on the 
coagulability of blood. Certain snake-poisons, thrombo-kinase, 
or nucleo-protein, and the artificially synthesised celloids of 
Grimaux, which give many of the colour reactions of protein 
bodies, will all in various doses induce intra-vascular clotting. 
Albino rabbits and the Norwegian hare in winter-time are 
generally regarded as immune to an injection of the last two 
bodies (Pickering), but, as E. H. Starling has pointed out, the 
statement is inaccurate for albino animals. 
The injected peptone is a digestive product, obtained by the 
action of trypsin. It is a mixture of albumoses and probably 
other less-known substances. Pick and Spiro consider that 
a heat-resistant body, peptozym, which is without influence 
upon extra-vascular blood, is the essential agent which affects 
intravascular plasma. The behaviour of peptone-plasma is 
inconstant. It may clot after a time spontaneously, but may 
do so quickly or not at all. Witte’s peptone, in doses below 
2 centigrammes per kilo body-weight, hastens coagulation, 
but above this dose it exerts a retarding influence (W. M. 
Thompson!). Water, weak acetic acid, or a stream of carbon 
dioxide, induces coagulation in peptone-plasma, even when this 
is free from leucocytes (Wooldridge). From a mass of conflicting 
statements it would appear that peptone-plasma contains throm- 
bogen, kinase, and calcium ions, but no thrombin. It is probable 
that, like normal plasma which contains some anti-thrombin, an 
excess of this substance is present, and its development is due 
to a reaction of the organism following the introduction of 
peptozym. That anti-kinase is also present is doubtful, since 
1 Journal of Physiology, vol. xx. 1896. 
