The Action of " Peptone" on Blood and Immunity thereto. 377 



blood. If 03 grm. per kilogramme of " peptone " is injected, the per- 

 centage in the blood is 0"45, or 0'9 if the larger quantity is used. 



If, from a pithed cat which is breathing only air for at least 15 minutes, 

 arterial blood is obtained through a paraffined cannula with only smooth 

 surfaces exposed to the blood, then less than Schmidt-Mulheim's minimal dose 

 for the dog will produce, in the more resistant cat, an unequivocal anti- 

 coagulant action in vitro, even in uncoated glass vessels. When the concen- 

 tration of " peptone " is increased, but is still 33 per cent, less than Schmidt- 

 Mulheim's larger amount, the results in vitro are parallel to those following 

 the injection of " peptone " into the circulation of the living animal. 



These data warrant the following conclusions : — 



1. " Peptone," even in small quantities, acts directly on the constituents of 

 the blood. 



2. The apparent difference found by other observers between the action of 

 " peptone " in vivo and its action in vitro is clue to the changes towards 

 clotting which take place in blood shed without special precautions to preserve 

 its surface conditions. 



3. It is superfluous to assume that the anticoagulant action of " peptone " 

 in vivo is due to the secretion of antithrombin either by the liver or by the 

 endothelial cells of the vascular system. 



On the Siqoposed role of Leucocytes in the Anticoagulant Action of ' " Peptone." 



Delezenne (40) considered that the first action of " peptone " on blood is 

 leucolysis yielding two substances : leuconuclein which hastens coagulation 

 and leucohistone which retards it. These both circulate through the liver where 

 the former is retained. The latter remains circulating. Several workers 

 including Halliburton and Brodie (41), Falloise (42) and Dastre and Studel (43) 

 however deny that " peptone " on injection causes leucolysis. Even if this 

 process does occur there appear to be no grounds other than pure speculation 

 for the supposed liberation of these substances into the blood stream. 



Nolf (44) maintained that under normal conditions an unknown substance 

 is produced by the leucocytes which acts upon the endothelium of the liver 

 and stimulates it to secrete antithrombin. The injection of "peptone" 

 enhances this process and the excess of antithrombin accounts for the 

 retarded coagulability of peptone blood. 



Having demonstrated that the liver is not necessary for the production of 

 the anticoagulant action of " peptone," it becomes of interest to enquire 

 whether the leucocytes are concerned in this phenomenon. To this end 

 Experiments 14-20 were devised. 



Cats were bled through paraffined cannula? into paraffined centrifuge tubes 



