260 Dr. L. C. Wooldridge. On the [Apr. 16, 



the surface and underground waters with which it conies into contact 

 as it rises through the volcanic duct, the violence of the eruption 

 being in exact proportion to the quantity which so gains access. 



IV. " On the Fibrin-yielding Constituents of the Blood Plasma." 

 By L. C. Wooldridge, M.B., D.Sc, Demonstrator of Physi- 

 ology in Guy's Hospital. From the Laboratory of the 

 Brown Institution. Communicated by Professor Michael 

 Foster, Sec. R.S. Received March 26, 1885. 



There is no doubt that from every variety of blood plasma a proteid 

 body may be isolated, which can by appropriate means be converted 

 into fibrin. This body, which is known as fibrinogen, has been more 

 especially studied by Hammarsten. This observer has shown that 

 fibrinogen possesses characters which clearly distinguish it from the 

 other supposed factor in coagulation, viz., paraglobulin, and also that 

 solutions of fibrinogen will, when treated with fibrin ferment, give 

 rise to fibrin. The only objection possible to Hammarsten's experi- 

 ments is that the body which he isolated has either previously to or 

 during the process of isolation undergone alteration. That it is in 

 fact not the same body which is present in the circulating blood, but 

 that it is, so to say, a sort of nascent fibrin. My observations bear on 

 this point. 



Peptone plasma is obtained by injecting a solution of peptone into 

 the veins of an animal, and bleeding it directly afterwards. The 

 blood does not clot, and by means of the centrifuge the plasma is 

 obtained. The injection of peptone produces this effect by preventing 

 the interaction of leucocytes and plasma which normally takes place 

 in shed blood.* By repeated centrifugal ising, the whole of the 

 corpuscular elements can be removed from this plasma, and the pure 

 plasma thus obtained can be made to clot in the most complete 

 manner, giving rise to a large quantity of fibrin, and this without 

 the addition of any further proteid body, so that the plasma must 

 contain dissolved in it the mother substance or substances of fibrin. 



In a note presented to the Society a few weeks ago, I described a 

 new constituent of the plasma which gives rise to fibrin and to other 

 bodies concerned in coagulation. I need not refer at length in the 

 present paper to this new substance. It is separable from the plasma 

 by cooling the latter, and after its removal the plasma still yields a 

 large quantity of fibrin, and from this plasma, by Hammersten's 

 method, a body can be isolated, agreeing in all particulars with 

 Hammersten's fibrinogen, and clotting readily with fibrin ferment. 



* Wooldridge : " Zur Grerinirung des Blutes," " Archiv fur Physiol.," Jahrg. 

 1883, p. 389. 



