266 



Dr. W. D. Halliburton. 



2. The Precipitate produced by cooling Peptone Plasma (Wooldridge's 

 fibrinogen A). — The occurrence of this precipitate is evidently 

 rcgarded by Wooldridge as one of the most important facts upon 

 which his theory is founded. Here, again, I am willing to concede 

 the fact observed, but differ from Wooldridge with regard to its 

 interpretation. The chief point I wish to urge is that this precipitate 

 is obtained on cooling peptone plasma only, and from no other form of 

 plasma. I have repeatedly attempted to obtain such a pi-ecipitate by 

 cooling to 0° C. pure plasma from the veins of the horse,* salted plasma, 

 prepared by mixing blood with various proportions of different salts, 

 hydrocele fluid, and pericardial fluid, but in all cases with a negative 

 result. It, therefore, occurs in peptone plasma alone ; and that it is 

 due to the peptone is supported by the fact that if one takes an aqueous 

 solution of "Witte's peptone" and cools it to 0° C, a precipitate is 

 formed consisting of rounded granules, which were mistaken under 

 the microscope by several friends in the laboratory for blood-tablets. 

 I, moreover, found that this precipitate consists of heteroalbumose, 

 and when that substance (which as Neumeisterf has shown is more 

 soluble in water than has been hitherto supposed) has been removed 

 by dialysis and filtration, the remaining albumoses and peptones are 

 not precipitated by cold. The precipitate of heteroalbumose, which 

 is obtained by dialysis of saline solutions of 11 Witte's peptone," also 

 consists of similar rounded granules. 



Peptone plasma, it may be said, does not contain peptone or 

 albumoses ; or rather that it is difficult to discover them in " pepto- 

 nised hlood." It is undoubtedly difficult, because they are present 

 in such small proportion that they are obscured by the overwhelmingly 

 large amount of globulin and albumin present. But as Neumeister^ 

 has shown that they are, after injection into the circulation, excreted 

 by the kidneys, we must also conclude that they exist as such for a 

 time in the blood. 



How their presence there prevents coagulation it is difficult to 

 say ; it is possible that they may cause by their presence a change in 

 the normal proteids of the blood that prevents the formation of or 

 the action of the fibrin ferment. That peptone blood does differ in 

 one other important particular from normal blood, viz., in the heat 

 coagulation temperatures of its proteids, was shown by Wooldridge 



* I have found that if the plasma is completely frozen, that on subsequently 

 thawing it, coagulation sets in very quickly (in 10 — 20 seconds) ; this is probably 

 due to the crystals of ice breaking up the white corpuscles, many of which still float 

 in the plasma. Nauck also has noted this and gives a similar explanation (loe. ext., 

 p. 20). After removing these by centrifugalising for two hours in vessels surrounded 

 by ice, no such phenomenon occurs, and clotting does not set in for fully fifteen 

 minutes after thawing. 



f 'Zeitschr. Biol ,' vol. 24, p. 269. 



% Ibid., vol. 24, p. 281 et seq. 



