THE COAGULATION OF THE BLOOD. 377 



respiration primarily caused probably in the respiratory 

 centre. The nucleo-albumins, obtainable from various 

 organs, differ in some minor points. 



3. Protagon, the most abundant impurity in these 

 preparations, and the closely-related substance lecithin, are 

 not responsible for the clotting ; neither is the dilute 

 sodium carbonate which was used as a solvent. 



4. The nucleo-albumins do not accelerate the coagula- 

 tion of extravascular (dilute salted) plasma, and so contrast 

 very forcibly with fibrin-ferment. 



5. A few experiments with "peptone" and "leech extract" 

 confirm the hypothesis of Pekelharing, that these substances 

 hinder coagulation on account of their affinity for calcium. 



6. Our experiments lend no support to the theory of 

 Wright and Lilienfeld, that the negative phase of coagula- 

 tion (i.e., the production of non-coagulable instead of 

 coagulated blood) sometimes observed is produced by the 

 splitting off of a peptone-like substance from the nucleo- 

 albumin. There is no evidence of peptone or albumose in 

 the blood or urine of the animal under experiment, and the 

 properties of the albuminous moiety of nucleo-albumin 

 are entirely unlike those of peptone. 



7. Failure to produce intravascular clotting is partly ex- 

 plained by idiosyncrasies of the animals used, and partly by 

 certain factors in the preparation of the nucleo-albumin ; 

 these are discussed with full details and tables of analyses. 



8. There appears to be some evidence that the nucleo- 

 albumins active in producing clotting are preceded in the 

 cells themselves by similar substances which differ from them 

 in not possessing this remarkable physiological activity. 



9. Solutions of nucleo-albumins destroy the blood cor- 

 puscles. This, however, is chiefly due to their alkalinity, 

 and will not explain the thrombosis (intravascular clotting) 

 produced. Distilled water, for instance, is a powerful 

 solvent of blood corpuscles, but never produces intravascular 

 coagulation. Lowit has recently given a list of agents that 

 produce leucolysis (destruction of leucocytes) and states that 

 plus calcium chloride they always cause thrombosis. We 

 have repeated these experiments carefully, but were en- 



