96 POISONOUS PKOTEINS 



dovan who has shown that blood freshly defi- 

 brinated by shaking with glass beads causes 

 acute death when injected intravenously into 

 guinea-pigs and rabbits. In the former the 

 typical anaphylactic lung picture is seen after 

 death. When the dose is slightly sublethal 

 there is marked fall in temperature with subse- 

 quent fever. When the doses are smaller there 

 is marked fever. On standing from fifteen to 

 forty-five minutes defibrinated blood loses its 

 toxicity. Serum obtained by rapid centrifuga- 

 tion of defibrinated blood is poisonous. The 

 same is true of the deposited and once washed 

 corpuscles. When coagulation is delayed by 

 the presence of sodium citrate neither the su- 

 pernatant fluid nor the corpuscles are poison- 

 ous, but both become so when coagulation is in- 

 duced by shaking with porcelain beads. Doerr 

 has shown that blood received in paraffined ves- 

 sels becomes poisonous ; but when the coagula- 

 tion is complete the toxicity disappears. When 

 coagulation is made to proceed slowly by the 

 addition of hirudin solution or a 0.7 per cent 

 solution of colloidal silicic acid, it retains its 

 toxicity for several hours. 



The fact that extracts of normal tissue, when 

 injected intravenously, are poisonous is another 

 interesting fact. If the lungs of a rabbit be 



