Nov. 19, 1921 Hemotoxins from Parasitic Worms 421 



certain conditions that are not yet understood. Inasmuch as ces- 

 todes are not capable of causing anemia by direct abstraction of blood 

 or by lacerating the mucosa, the etiological role of a hemotoxin, if such 

 a substance can be demonstrated in forms that cause anemia, can hardly be 

 denied. The discovery of Schaumann and Ta\lqvist{i8g8) and the subse- 

 quent studies of Tallqvist (1907) and Faust and Tallqvist {1907) with 

 reference to the D. latum hemolysin are of great significance and mark 

 the beginning of the study of the pathogenicity of parasitic worms from 

 the point of view of intoxication. Despite the fact that D. latum ap- 

 pears to stand alone among cestodes capable of setting up a severe type 

 of anemia, there is some evidence that other cestodes are also capable of 

 bringing about anemia, perhaps not so intense as that produced by D. 

 latum. Railliet {1895), Neveu-Lemaire {1912), Hutyra and Marek 

 {19 1 3), and other writers on veterinary parasitology state that cattle 

 and sheep that are parasitized by tapeworms show clinical symptoms of 

 anemia. Adult cestodes parasitic in these ruminants belong to the 

 genera Moniezia and Thysanosoma. Only one species of the latter 

 genus is known in the United States, namely, Thysanosoma actinioides , 

 whereas several species of Moniezia occur in this country. Investiga- 

 tions by the present writer with reference to hemolysins in worms be- 

 longing to the genera Moniezia and Thysanosoma have yielded the 

 following results. 



A salt-solution extract of Thysanosoma actinioides powder made by 

 adding the powder to salt solution and allowing the extract to remain 

 at 8° C. for about 24 hours was found to be hemolytic to washed sheep 

 blood cells and rabbit blood cells. In one experiment 150 mgm. of 

 powder were extracted in 5 cc. of physiological salt solution overnight 

 at a temperature of 8°. The supernatant fluid was filtered and the 

 filtrate tested on washed rabbit blood cells. Equal parts of extract of 

 suspension of corpuscles showed complete hemolysis after 2 hours at 

 37°. Further experiments with salt-solution extracts of dried material 

 on washed sheep and rabbit blood corpuscles confirmed the presence of a 

 soluble hemolysin in this parasite. Thus, an extract prepared by adding 

 0.2 gm. of powder to 2 cc. of salt solution was tested on rabbit and 

 sheep blood corpuscles and yielded positive results. The action of the 

 hemolysin was comparatively slow. To tubes each containing 5 drops 

 of washed blood cells 5 and 10 drops, respectively, of the extract were 

 added and incubated at 37° for 2 hours; hemolysis was not evident in 

 the tubes. After an additional period of 18 hours during which the tubes 

 were kept in a refrigerator hemolysis was complete in the tube to which 

 10 drops of extract had been added and marked but incomplete in the 

 tubes to which only 5 drops of extract had been added. It should be 

 stated in this connection that in several instances salt-solution extracts 

 of dried T. actinioides were not destructive to red blood cells of sheep. 

 Whether the red blood cells of certain animals are more resistant than 



