Nov. 19, 1921 Hemotoxins from Parasitic Worms 411 



and a few drops containing worm particles were added to 0.5 cc. of a 5 

 per cent suspension of washed rabbit erythrocytes. After one hour's 

 incubation hemolysis was complete. A tube containing corpuscle sus- 

 pension alone showed no hemolysis. A repetition of this experiment 

 yielded similar results. 



From the foregoing experiments it appears that the hookworm hemoly- 

 sin is firmly bound to the cells of the parasite. In fresh worms a con- 

 siderable quantity of free hemolysin is probably present in tlie tissues 

 and fluids of the body, which is absorbed by the salt solution in the 

 course of extraction. Since the sediment of extracts of fresh worms has 

 been found to yield additional hemolysin after the first extraction, it is 

 evident that salt solution does not absorb all the hemolysin present in the 

 worms. The observation of Preti (1908) that tryptic digestion liberates 

 the hemolysin is further evidence of a close union between the hemolysin 

 and the cells of the worm. 



3. EXPERIMENTS WITH EXTRACTS OF ALCOHOLIC SPECIMENS 



The experiments described below were performed with extracts 

 obtained from specimens of Ancylostoma caninum which had been pre- 

 served in alcohol for about three years. Unless otherwise stated the 

 extracts were prepared as follows: The specimens were washed several 

 times in distilled water, dried at room temperature, and powdered in a 

 mortar; o. i gm. of the powder was suspended in 10 cc. of an 0.85 per cent 

 solution of sodium chlorid and extracted in a refrigerator for about 24 

 hours. The supernatant fluid was then tested on the washed erythro- 

 cytes of rabbit and sheep as follows. 



Experiment 12. — Five drops of a 5 per cent suspension of rabbit 

 corpuscles plus 3 drops of extract showed complete hemolysis at a tem- 

 perature of 37° C. in 2 hours. Equal parts of extract and corpuscle 

 suspension showed complete hemolysis in 1^2 hours. This experiment 

 was controlled as usual. 



Experiment 13. — Five drops of a 5 per cent suspension of washed 

 sheep corpuscles were mixed with 10 drops of extract and incubated for 2 

 hours without producing any hemolysis. A similar experiment was 

 performed a few months later with negative results, despite the fact that 

 after incubating the mixtures of corpuscles and extract for 2 hours 

 they were kept in a refrigerator for 18 hours longer. 



Experiment 14. — Five drops of a 5 per cent suspension of rabbit 

 corpuscles were not hemolyzed by 5 drops of extract. 



Experiment 15. — A 5 per cent suspension of washed guinea-pig 

 corpuscles resisted hemolysis after remaining in contact for 3 hours at 

 a temperature of 37° C. with an extract of alcoholic specimens made by 

 extracting 200 dried specimens in 6 cc. of physiological gait solution and 

 mixing 3 drops of extract with 2 drops of the suspension of corpuscles. 

 Fifteen drops of the extract in contact with 3 drops of the blood suspen- 

 70495°— 21 3 



