Coagulant of the Venom of Echis carinatus. 



181 



opening the chest immediately after death the lungs were observed to 

 collapse rapidly ; blood obtained from the heart clotted slowly at room 

 temperature ; no clots were found in the heart and great blood-vessels. 



On microscopical examination of sections of the viscera of rabbits which 

 had received by intravenous injection lethal amounts of red-cell stromata, 

 fibrin masses were sometimes, but not invariably, found in the blood-vessels 

 of the lungs, being present in very sparse numbers, even though relatively 

 large quantities of stromata (i.e., as much as is obtainable from 4 c.c. to 12 c.c. 

 of rabbit's red cells per kilogramme of body weight of the animal injected) 

 were introduced. It is to be noted also that no obviously defective formation 

 of fibrin in blood obtained from the heart could be observed, clotting generally 

 resulting in the formation of a firm coagulum retracting normally in the 

 'course of 24 hours ; occasionally, however, the clot formed was distinctly soft. 

 Coagulation was usually delayed, the period of onset of coagulation at 37° C. 

 being one to six minutes.* 



The intravascular injection of thrombokinase in the form of peptone was 

 carried out in a series of experiments of which the following is an example : — 



Experiment 3. — Into the vein of the ear of a rabbit weighing 542 grm., 

 24 c.c. of a 9-per-cent. solution of Witte's peptonef (the solution was 

 observed to be alkaline to litmus paper) was injected at the rate of 2 c.c. per 

 minute ; 10 minutes after the completion of injection 5 c.c. of blood were 

 removed from the internal carotid artery ; the blood remained fluid at the 

 end of 50 minutes at room temperature (17° C), but at the end of 70 minutes 

 a soft clot had formed which after 2 hours had become firm and was found 

 to be considerably retracted ; 2 c.c. of blood removed from the vein of the 

 ear shortly before injection formed a firm clot at the end of 12 minutes. 



On microscopical examination of the viscera of rabbits killed 5 to 

 30 minutes after intravenous injection of a solution of peptone no fibrin 

 masses were found in the blood-vessels of the lungs or elsewhere. No 

 obvious defect of fibrinogen was observable after the injection of peptone, 

 the blood clotting slowly, but after a time forming a firm coagulum, which 

 retracted to about the normal extent. The amount of peptone (which it 

 should be noted was not prepared from the flesh of the rabbit) injected in 

 these experiments ranged from 0'3 to 7 - 3 grm. per kilogramme of body 

 weight. Blood obtained from the internal carotid artery 10 to 20 minutes 

 after injection was in no case permanently liquid, though as already 



* J. O. W. Barratt and W. Yorke, loc. cit. 



t This amount corresponds to 4 grm. of peptone per kilogramme body weight. 



