4o8 Journal of Agricultural Research voi. xxn. no. s 



ExPBRiMEjNT 4. — ^Twelve drops of extract of fresh worms were heated 

 for 30 minutes at a temperature ranging from 56° to 58° C. The addi- 

 tion of 0.5 CO. of washed dog corpuscles from the same lot as that used 

 in experiment i resulted in partial hemolysis after one hour of incuba- 

 tion at 37°. The tube was kept in a refrigerator overnight and showed 

 almost complete hemolysis the next day. 



Experiment 5. — ^A quantity of extract of fresh worms was heated at 

 60° to 65° C. for 50 minutes. To two tubes each containing 10 drops 

 of extract that had been thus heated there were added 5 drops of rabbit 

 and sheep corpuscles, respectively, of the same concentration as noted 

 in experiments 2 and 3. No hemolysis was produced after two hours' 

 incubation at 37°. The tubes were kept in a refrigerator overnight 

 and showed slight hemolysis the following day. 



Experiment 6. — ^Twelve drops of extract of fresh worms were heated 

 to boiling, and after cooling they were added to 0.5 cc. of suspension 

 of dog corpuscles of the same concentration as in experiment i and 

 were incubated for one hour, but no hemolysis was produced. After 

 remaining in an ice box overnight the tube showed but a trace of hemo- 

 lysis. Similar results were obtained when rabbit and sheep corpuscles 

 were used. Control tubes showed no hemolysis. 



A second series of experiments with extracts of fresh worms was per- 

 formed several weeks later. The details of these experiments follow. 



The extract referred to as extract II of fresh worms was prepared by 

 macerating 29 live specimens of Ancylostoma caninum ^ obtained from 

 five dogs shortly after the animals had been killed. The macerated 

 material was suspended in 3 cc. of physiological salt solution, shaken 

 vigorously, and allowed to extract at room temperature for about an 

 hour before it was tested for its hemolytic power. Part of the extract 

 was kept overnight in a refrigerator and was used the following day. 

 The suspension of corpuscles and extract was incubated at 37° C. for 

 periods shown in the table, the results were noted, and the tubes were 

 then placed in a refrigerator for an additional period of 18 hours, when 

 the final results were read. 



The data presented in Table III show that rabbit and dog corpuscles 

 are more susceptible to hookworm hemolysin than the corpuscles of 

 swine and cattle. Despite the fact that the latter were not hemolyzed 

 by the extract used in these tests, they are not absolutely resistant to 

 extracts of dog hookworms, as will be shown in another section of this 

 paper. 



' These specimens were washed several times in physiological salt solution. 



