74 SCIENCE PROGRESS 
10. MoRPHOLOGY OF BLOOD-COAGULATION 
Recent papers of Loeb on the process of coagulation in 
vertebrate blood, those of Ducchesi, Biirker, and more recently 
Nolf, deal with this part of the subject. Loeb, whose view 
corresponds in some respects to that of Noli, who worked with 
the blood of vertebrates, distinguishes two distinct phases in 
coagulation : 
1. The stage of agglutination of leucocytes in arthropoda 
and crustacea, and of blood-platelets in mammals. 
2. The formation of fibrin from this agglutinated stage. 
Loeb finds that peptone does not hinder clotting in the lobster, 
neither does kinase from vertebrates induce coagulation in the 
blood of invertebrates. In the blood of Limulus he states that 
a fibrinogen coagulable at 56° does not exist, and that this tem- 
perature does not interfere in any way with the first stage of 
coagulation. On dilution with water the blood of this animal 
shows agglutination of leucocytes, and the remaining liquid clots 
easily on the addition of muscle-extract from the same animal. 
The macroscopic appearances on glass in shed blood to which 
Ducchesi! has drawn attention as the first alteration which 
blood undergoes outside the body, is due to an accumulation of 
platelets, and is a phenomenon entirely absent in peptone or 
hirudin-blood. This is also a definite agglutination process. 
Every observer, however, has seen that the bodies termed 
“platelets” are preserved in both these fluids. But agglutina- 
tion rarely occurs. Regarded purely from the morphological 
point of view, it is possible that both inside and outside the 
body any damage to the blood-plasma is followed firstly by 
production and secondly by agglutination of previously non- 
existent platelets,? and then this stage is succeeded by the 
subsequent appearance of fibrin. As far as the relation of these 
phases to the coagulation process is concerned, this view is 
similar to that recently proposed by Birker. 
1 Hofmetsters Bettrige, iii. p. 378. 
* Iam able to confirm a recent observation of Marino (Compiles rend. No. 4, 
1905), who observed that when rabbits’ blood is received into so much absolute 
alcohol that this is only slightly diluted, no platelets can be demonstrated to 
exist. It is inconceivable that they are destroyed, since the same blood mixed 
with 95 per cent. alcohol yields an abundant supply. This experiment, therefore, 
lends no support to the view that platelets exist in undamaged circulating blood. 
