Nov. 19,1921 Hemotoxins from Parasitic Worms 381 



parasitic worms, the experimental evidence on the subject is somewhat 

 contradictory, due no doubt to the fact that different investigators 

 experimented under different conditions. The study of the effects of 

 extracts of parasites on hving animals presents numerous difficulties and 

 complications and may lead to contradictory results unless suitable 

 precautions are taken to control various extraneous factors. More accu- 

 late studies on the effects of toxic products may be carried out in vitro, 

 provided the toxic substance in question has affinity for tissues and cells 

 available for such experiments. As is well known, red blood cells serve 

 as excellent indicators of test-tube reactions in v/hich hemotoxic sub- 

 stances are involved, and in the case of toxic products of parasitic origin, 

 experiments with red blood cells are of great importance in view of the 

 fact that in many parasitic infestations anemia is a characteristic symp- 

 tom. The effects of extracts of parasitic worms on red blood cells, 

 especially of extracts of those parasites that are known to cause anemia, 

 are thus of interest with reference to the possibility that the parasites in 

 question secrete specific toxins for the blood (hemotoxins). 



II. REVIEW OF LITERATURE ON HEMOTOXINS IN PARASITIC WORMS 



The same year in which Ehrlich (iSg8) announced the discovery of a blood toxin 

 produced by Bacillus tetanus, Schaumann and Tallqvist (i8g8) reported the discovery 

 of a blood toxin in the broad tapeworm of man {Diphyllohothrium latum). Ehrlich 's 

 discovery in the field of bacteriology served as a stimulus to the study of bacterial 

 hemolysins by various investigators and was followed by a series of investigations into 

 the nature and action of these hitherto unknown products of bacterial growth. Al- 

 though the discovery of Schaumann and Tallqvist did not arouse the same degree of 

 activity in parasitology as Ehrlich 's discovery aroused in bacteriology, the results of 

 their investigations were not without influence on subsequent researches in parasit- 

 ology, the influence being especially marked in connection with studies on the causes 

 of the anemia that occurs in cases of infestation with hookworms. 



The facts published by Schaumann and Tallqvist {1898) may be briefly summarized 

 as follows: 



Macerated material of Diphyllobothrium latum contains a hemolytic substance active 

 in vitro as well as in vivo. Peptic digestion liberates the hemolysin from the tissues 

 of the parasites. The introduction of D. lattim material into dogs parenterally or peros 

 leads to a marked reduction in the number of erytlirocytes. 



In a later paper Tallqvist {1907) gives a more detailed account of the nature of the 

 hemotoxic secretions of Diphyllobothrium latum. The hemolytic principle is closely 

 bound to the cells of the parasite and is but slightly soluble in water and physiological 

 salt solution. By means of peptic digestion and alcohol or ether extraction it becomes 

 dissociated from the tissues and goes into solution. The hemolysin is thermostabile 

 and does not cause the development of antibodies when injected into animals. In 

 these respects it resembles normal tissue hemolysins. Tallqvist fotmd, moreover, 

 that D. latum contains not only a hemolysin but also a hemagglutinin. The latter is 

 soluble in water in contrast to the water-insoluble lipoidal hemolysin. The hemagglu- 

 tinin as well as the hemolysin is nonspecific. The potency of these agents varies, 

 however, for different species of red blood corpuscles. 



Faust and Tallqvist (1907) studied the Diphyllobothrium hemolysin as to its chemi- 

 cal nature. These investigators found that extraction of the entire worm material in 

 ether removed all the hemolysin from the tissues of the parasite, since the removal of 



