62 SCIENCE PROGRESS 



3. The recognition by Fuld and Spiro and by Morawitz 

 that the term " thrombin " is applied to bodies which possess 

 quite different properties. 



Contrary to the results of previous observers in 1880, 

 Edelberg, 1 a pupil of Schmidt, obtained intra-vascular clotting 

 by the injection of solution of fibrin-ferment. In confirmation 

 of the views of Schmidt that the fibrin-ferment was directly 

 or indirectly a product of the leucocytes, Rauschenbach 2 in 

 particular showed that not only leucocytes of the blood, but the 

 cell-protoplasm of almost every tissue in the body, also yeast- 

 cells (Wright), could markedly induce or accelerate coagulation 

 in salted plasma, cooled plasma, and some, but not all, specimens 

 of hydrocele and ascitic fluid. Tissues rich in nuclei possess 

 this property not only in vitro, but when injected into the 

 circulation — a fact which was definitely established by Foa 

 and Pellacani, 3 who observed, moreover, that the tissue-extracts 

 from the most varied sources, with the exception of the spleen, 

 could induce intra-vascular clotting. Wooldridge i in particular 

 confirmed these results, and in a remarkable paper showed 

 that solutions of tissue-extract can not only cause a sudden 

 death and produce extensive intra-vascular clotting, especially 

 in the portal system, but that in dogs a definite dose per kilo 

 body-weight can also produce conditions where the shed blood 

 is found to be incoagulable. Further, a " Schutzimpfung auf 

 chemischem Wege" could be demonstrated. This, the earliest 

 example of an acquired immunity conferred by injection, was 

 proved by showing that a small dose of injected tissue-extract, 

 which Wooldridge subsequently termed B-fibrinogen, rendered 

 a dog immune to a subsequent lethal dose of the same sub- 

 stance. These suggestive experiments, together with others 

 on recognition of phosphorus in the extracts and his work 

 on peptone-plasma led Wooldridge, like Rauschenbach, to 

 speak of blood-plasma as protoplasma, and to hold that 

 circulating blood contained within itself all that was essential 

 for the coagulation process. The existence of fibrin-ferment 

 played no part in his theory ; both the coagulation and 

 non-coagulation of blood was dependent upon the relations 



1 Arch. f. exp. Path. u. Pharmak. ii. p. 283, 1880. 



2 Inaugural Dissert. Dorpat, 1883. 



3 Bir. din. di Bologna, p. 241, 1880. 



4 Du Bois' Archiv, 1881. 



