THEORIES OF CO A G ULA TION. 1 7 5 



administered nucleo-proteids or snake venom be employed, then these 

 additions do not produce coagulation. 1 In view of the fact that 

 calcium chloride will not, under these circumstances, produce coagula- 

 tion, the hypothesis of Freund and Pekelharing, that " peptones " 

 deprive blood of its coagulability by combining with its calcium salts, 

 loses probability. 



Peptone injected intravenously rapidly disappears from the blood. 2 The 

 action of peptone differs from that of leech extract, in that a second dose, 

 given soon after the action of the first dose has passed off, fails to produce an 

 effect on coagulability. Moreover, the blood of a " peptonised " dog confers 

 immunity from the action of peptone, if injected intravenously into a second 

 animal. 3 



The properties of peptone plasma, and the effects of leucocytes and 

 their saline extracts upon the coagulability of blood, were carefully 

 studied by Wooldridge. This observer found, as already stated, that if 

 peptone plasma be kept for a time at a precipitate forms, which takes 

 the form, under the microscope, of minute discoid particles, almost exactly 

 similar to blood platelets. The substance thus precipitated was termed 

 " A-fibrinogen " by Wooldridge, while he named the substance precipit- 

 able by half -saturation with NaCl " B-fibrinogen " ; this is the same 

 thing as fibrinogen as ordinarily understood. After the removal of the 

 A-fibrinogen, the coagulability of peptone plasma by C0 2 and other 

 conditions is greatly diminished or altogether lost, but is restored on 

 dissolving the A-fibrinogen again with the aid of warmth. 



Wooldridge's A-fibrinogen is also obtainable, as Wright has shown, by 

 cooling oxalate plasma, and it is probably composed mainly, if not entirely, 

 of nucleo-proteid. It has been shown by Hammarsten that if by prolonged 

 cooling and filtration it is removed as much as possible from oxalated plasma, 

 the plasma will not coagulate on the addition of sufficient lime salts to more 

 than balance the excess of oxalic acid, but that, if the precipitate be collected 

 and treated with lime salts, it furnishes, on subsequently removing the 

 lime by oxalate, a powerful thrombin or fibrin ferment. Hammarsten 

 accordingly terms the substance in question, which is precipitated by cold 

 from plasma, prothrombin, and considers that it can only be converted into 

 thrombin by the action upon it of lime salts. Pekelharing regards the 

 precipitate in question as composed of nucleo-proteid, and considers that the 

 lime acts by combining with it to form fibrin ferment. 



The addition of lymph cells (washed with 0'6 per cent. NaCl solution) 

 to peptone plasma causes its coagulation outside the body, and also acceler- 

 ates the coagulation of ordinary blood in vitro, whereas the intravenous 

 injection of salt solution holding these washed lymph cells in suspension 

 produces an incoagulable condition (negative phase) of blood, which 

 does not then coagulate, even on withdrawal. But on addition of some 

 of this fluid, holding cells in suspension, to such blood after withdrawal, 

 coagulation is rapidly produced. The loss of coagulability of peptone 

 plasma is not due, as was supposed by A. Schmidt, to the disappearance 

 and disintegration of leucocytes, for, as Wooldridge showed, the addition 



1 C. J. Martin, op. cit., pp. 35-40. According to Dastre and Floresco, the chief cause of 

 the lack of coagulation in peptone plasma is its high alkalinity (Arch, de jihysiol. norm, et 

 path., Paris, 1897, p. 216). 



2 Schmidt-Mulheim, loc. cit. 



3 Contejean, Arch, dephysiol. norm, etpath., Paris, 1895. 



