1885.] A New Constituent of the Blood and its Import. 69 



phrase " material system," we include the gyroscopic systems whose 

 motions produce the same effect as the potential energy of the 

 original system, and two configurations are not supposed to coincide 

 unless the configurations of these systems coincide also. 



V. " On a New Constituent of the Blood and its Physiological 

 Import." By L. C. WOOLDRIDGE, D.Sc, M.B., Demonstrator 

 of Physiology in Guy's Hospital. Communicated by Pro- 

 fessor M. Foster, Sec. R.S. Received December 16, 1884. 



In a paper on the Origin of the Fibrin Ferment, published in 

 •" Proc. Hoy. Soc," vol. 36, I showed that there exists, dissolved in 

 the plasma, a body which can give rise to fibrin ferment. 



I have proceeded with my investigations, and have succeeded in 

 making some additions to our knowledge of this subject, which I 

 here describe. As my researches are not complete, I confine myself 

 to as brief an account as possible. 



The subject is best studied in the blood of peptonised dogs. But 

 as I showed in the above quoted paper, similar results are obtained 

 from normal salt plasma, so that the results are not peculiar to 

 pepton blood. The body, the presence of which gives rise to fibrin 

 ferment, can be isolated from pepton plasma in the following very 

 simple manner: — The plasma having been completely freed from all 

 corpuscular elements by means of the centrifuge, is cooled down to 

 about 0°. The plasma, which was previously perfectly clear, becomes 

 rapidly turbid, and after standing for some time in the cool, a very 

 decided flocculent precipitate forms. I have already described this 

 observation in a short note, " Ueber einen neuen Stoff des Blut- 

 Plasmas," in du Bois Reymond's " Archiv fur Physiologie," but it is 

 necessary for me to allude to it here. 



Now it is this body which gives rise to the fibrin ferment. So long 

 as the former is present in considerable quantity the latter clots 

 readily on passing through it a stream of carbonic acid, or on dilution, 

 and at the same time a very considerable quantity of fibrin ferment 

 makes its appearance. 



By prolonged cooling the greater part of this substance can be 

 removed, and with its gradual removal the plasma clots less and less 

 readily with C0 2 , and less and less ferment is formed, till finally it 

 becomes practically incoagulable, i.e., forms only a faint trace of fibrin 

 after several days. If some of the substance be again added to the 

 plasma, it regains its power of clotting with C0 2 . 



(The substance must be added before it has stood very long : see 

 under.) 



