4IO Journal of Agricultural Research voi. xxii. no. 8 



the extract of fresh worms, which is opalescent, the extract of powdered 

 material remained quite clear. 



Experiment 9. — To four tubes labeled from i to 4, each containing 5 

 drops of a 5 per cent suspension of washed rabbit corpuscles, there were 

 added, respectively, 3, 5, 8, and 10 drops of the extract. To a fifth tube 

 containing an equal quantity of corpuscles there were added 10 drops of 

 physiological salt solution in order to control the results of the experi- 

 ment. The tubes were incubated for i hour at 37° C, and kept for 18 

 hours longer in a refrigerator, after which the final results were read. 

 Tube I showed no hemolysis, while tubes 2, 3, and 4 showed complete 

 hemolysis. The control tube showed no hemolysis. 



Additional experiments with the same extract and the same corpuscles 

 showed that the hemolytic action was very slow, since 10 drops of the 

 extract in contact with 5 drops of the suspension of corpuscles failed to 

 produce hemolysis after 2 hours' incubation at 37° C, but after an 

 additional period of 18 hours in a refrigerator the tube showed complete 

 hemolysis, whereas the control tube showed no trace of hemolysis. 



Experiment 10. — The extract of dried worms was tested on a 5 per 

 cent suspension of washed corpuscles of cattle and swine as follows: To 

 four tubes each containing 0.2 cc. of corpuscles there were added, respec- 

 tively, I, 2, 3, and 5 drops of the extract, and the tubes were incubated 

 for I hour. None of the tubes showed hemolysis. After remaining in a 

 refrigerator overnight the following results were noted. 



Cattle corpuscles : The tubes containing i and 2 drops of the extract 

 showed partial hemolysis, whereas the tubes containing 3 and 5 drops of 

 extract showed complete hemolysis. 



Hog corpuscles: No hemolysis was observed in any tube. 



The foregoing experiments were controlled as usual. 



In the experiments described above the extract was not filtered but 

 was added to the suspension of corpuscles together with some particles of 

 worm material. 



In a second series of experiments performed several weeks later it was 

 found that washed rabbit blood corpuscles were unaffected when placed 

 in contact with an extract of dried hookworms, incubated for 3 hours, 

 and then kept in a refrigerator for an additional period of 18 hours. While 

 no record was made as regards the introduction of particles of worm 

 material into the tubes containing the suspension of corpuscles, it is 

 probable that the clear supernatant fluid alone was added. 



A repetition of the experiment on a later date yielded the following 

 results. 



Experiment m — ^A small quantity of coarsely powdered worm mate- 

 rial was extracted in physiological salt solution, filtered, and the filtrate 

 tested on washed rabbit blood corpuscles. No hemolysis was produced. 

 To the material which had thus been extracted a small quantity of physio- 

 logical salt solution was added, the contents were thoroughly agitated, 



