Nov. 19, 1921 Hemotoxins from Parasitic Worms 425 



worms belonging to the genera Ascaris, Ancylostoma, and Bustomum are 

 inhibited at 8°. The hemolytic effect of Thysanosoma actinioides extract 

 is not inhibited at this temperature, however. This fact is important and 

 clearly differentiates hemolysins of nematodes from the hemolysin of 

 T. actinioides. In this respect, too, nematode hemolysins resemble bac- 

 terial hemolysins. 



Finally, the action of hemolysins from parasitic worms is inhibited by 

 normal serum. The antilytic property of the serum is thermostabile 

 (Weinberg, igo8, and the experimental results obtained by the present 

 writer). Tissue lysins, too, are inhibited by normal serum. Certain 

 bacterial hemolysins are similarly susceptible to normal serum. 



On the basis of this discussion nematode hemolysins may be character- 

 ized as relatively simple substances, thermolabile or thermostabile, 

 depending on the species from which they are obtained, inactive at low 

 temperatures (6° to 8° C), inactive in the presence of normal serum, 

 nonspecific, soluble in alcohol and in physiological salt solution. 



Cestode hemolysins, so far as they have been investigated, are rela- 

 tively simple bodies, thermostabile, active at low temperatures, inactive 

 in the presence of normal serum, nonspecific, soluble in alcohol. 



The question naturally arises whether toxic products from parasitic 

 worms are liberated from the bodies of the latter and get into the circula- 

 tion of the host. Blanchard (1903), while accepting the evidence in 

 favor of the view that parasitic worms elaborate toxic products, appears 

 to doubt the etiological significance of these toxic substances because 

 of the possibility that they are either not liberated by the worms or if 

 liberated may be thrown out of the body before they can injuriously 

 affect the host. The available evidence on this question appears to indi- 

 cate that hosts harboring parasitic worms actually absorb the toxic 

 products of the latter. The serological evidence in favor of this view has 

 already been referred to. It may be added that the fact reported by 

 Guerrini {1908) with reference to the presence of hemolysins in the blood 

 serum of hosts harboring Fasciola hepatica and the findings of De Blasi 

 that hemolysins occur in the blood serum of hosts harboring Ancylostoma 

 duodenale tend to confirm the belief that parasites liberate their toxic secre- 

 tions and that these secretions get into the circulation of the host. Wein- 

 berg {1908) has made some interesting observations on the tissues of hosts 

 harboring parasitic worms which argue directly in favor of the absorption 

 by the host of toxic products liberated by the worms. Weinberg exam- 

 ined histologically the organs of 32 horses infested with strongyles and 

 obtained the following results: In the blood vessels he found a large 

 number of mononuclear leucocytes containing iron granules. He also 

 found similar granules in the spleen, liver, in the conjunctival tissue, in 

 the Malpighian tubules and in the convoluted tubules of the kidneys, 

 and in the canals of the right kidney. Histological examinations by the 

 same investigator of organs from 30 monkeys infested with a species of 



