Nov. 19, 193 1 



Hemotoxins from Parasitic Worms 



413 



tubes were kept 18 hours longer in a refrigerator, with a resultant faint 

 indication of hemolysis. Washed erythrocytes from the same rabbit 

 were highly susceptible to the extract, since 10 drops of a 3 per cent sus- 

 pension of corpuscles were completely hemolyzed by 5 drops of extract 

 in about 20 minutes. 



Experiment 20. — ^To a series of tubes each containing 3 drops of a 

 5 per cent suspension of washed dog erythrocytes used in an earlier ex- 

 periment and included in Table I there were added 5 drops of extract 

 II of fresh worms and various blood sera diluted with an equal quan- 

 tity of physiological salt solution and heated at 59° C. for 30 minutes. 

 The data and results of these experiments, including the controls, are 

 given in Table IV. 



Table IV.— Effects of various sera on hookworm hemolysinO' 



Tube 



N0.6 



Kind and quantity of diluted sera. 



3 drops (horse serum) 

 3 drops (dog serum) . . 

 3 drops (rabbit serum 

 No serum 



Results after 

 3 hours' in- 

 cubation at 

 37° C. 



+ + + 



Results after 



18 hours 

 longer in re- 

 frigerator. 



+ 

 + + + 



(I + -I- -f indicates complete hemolysis, -f indicates slight hemolysis. — indicates absence of hemolysis. 

 b Three drops of a 2 per cent suspension of washed dog corpuscles and 5 drops of extract II of fresh worms 

 were used in this series of experiments. 



5. EFFECT OF COLD ON HOOKWORM HEMOLYSIN 



Experiment 21. — Dog corpuscles which were found to be highly 

 susceptible to an extract of fresh worms at 37° C. remained intact after 

 being kept for 5 hours on ice in contact with a quantity of extract suffi- 

 cient to destroy the corpuscles at 37° in 30 minutes. The removal of 

 the supernatant fluid following rapid centrifugation showed that it had 

 completely lost its hemolytic potency, since it failed to hemolyze sus- 

 ceptible dog corpuscles after remaining in contact with them for 2 hours 

 at a temperature of 37° followed by 1 8 hours at a temperature of about 10° 



Experiment 22. — The foregoing experiment was repeated, substitut- 

 ing susceptible rabbit corpuscles for dog corpuscles, with similar results. 



The loss of the hemolytic property of the extract in contact with sus- 

 ceptible corpuscles at a low temperature can not be attributed to a 

 possible injurious effect of cold, since it was found that the hemolytic 

 potency of the extract was not injured after standing directly on the ice 

 for 18 hours. Washed sheep corpuscles were readily hemolyzed by the 

 refrigerated extract, whereas a control tube containing corpuscles alone 

 showed no hemolysis. 



Experiment 23. — Six drops of dog blood corpuscles from the same lot 

 as that described in experiment 7 were mixed with 10 drops of extract II 



