Nov. 19, 1921 Hemotoxins from Parasitic Worms 383 



observation that human red blood corpuscles are destroyed when placed in contact 

 with the cervical glands isolated from hookworms (species not given but presumably 

 A. duodenale), but subsequent investigation showed that the hemolysin is not limited 

 to the cervical glands. 



Loeb and Smith (1904) in the course of experiments wath salt-solution extracts of 

 the dog hookworm (Ancylosioma caninum), found that these extracts showed no hemo- 

 lytic properties and left the blood still intact and uncoagulated after being in contact 

 with it for 17 hours. Reference to the work of these investigators on the anticoalgula- 

 ting property of hookworm extract {A . caninum) will be made elsewhere in this paper. 



Liefmann (7905) found that in two out of three experiments salt solution extracts of 

 Ancylosioma caninum produced slight hemolysis of dog blood. This writer observed 

 intact erythrocytes in the intestines of the worms and therefore came to the conclusion 

 that the parasites do not secrete a hemolysin. Liefmann fails to state whether or not 

 he washed the blood corpuscles before testing them against hookworm extract. 



Preti {1908) foimd that the Old World hookworm of man {Ancylosioma duodenale) 

 contains a hemolysin insoluble in salt solution but soluble in ether and alcohol. He 

 states that tryptic digestion liberates the hemolysin and renders it soluble in water. 

 He found the hemolysin to be resistant to boiling for three hours and nonspecific, since 

 it was equally potent against the blood corpuscles of several other species of animals 

 as well as man. 



In the course of his investigations concerning ancylostomiasis and beriberi, Noc 

 {1908) found that physiological salt-solution extracts of the hookworm of man {Necator 

 dmericanus) are hemolytic to the washed red blood corpuscles of man. He states that 

 the hemolysin withstands a temperatiu-e of 80° C. for one hour without injury to its 

 potency. Noc found that whereas the blood serum of patents suffering from severe 

 ancylostomiasis and beriberi contained no antihemolysins, that of normal persons and 

 of those recovering from these diseases was antihemolytic. 



De Blasi {1908) examined the blood serum of 12 human subjects infested with hook- 

 worms {Ancylosioma duodenale) and found that after the serums were heated for 30 

 minutes at 56° to 62° C. they acquired hemolytic properties. Before heating, the 

 serums in question were not hemolytic. Heating the serum evidently destroyed some 

 antibodies which neutralized the potency of the hemolysin. The heated serum of 

 normal persons, according to this writer, did not contain any hemolysins. 



Whipple {1909) records tests of salt-solution eyLtractsoi A ncylostotna caninum, A. 

 duodenale, and Necator americanus on unwashed citrated blood of man, dog, and rat. 

 He states that he found a weak hemolysin in the three species of hookworms exhibiting 

 similar properties, namely, nonspecificity, susceptibility to boiling which destroys it, 

 and distribution in all parts of the body of the worms. According to Whipple, the 

 hemolysin is only demonstrable in concentrated extracts, and probably bears no 

 relation to the secondary anemia of ancylostomiasis. 



lyoeb and Fleisher {1910) state that a salt-solution extract of Ancylosioma caninum, 

 containing as much as 5 mgm. of the powdered worm material in i cc. of salt solution 

 did not produce any hemolytic effect on the washed erythrocytes of the dog. These 

 writers also state that lecithin used in doses in which it alone produced no hemolytic 

 effect failed to activate A. canimim extract. Loeb and Fleisher admit the possibility 

 that the temperature at which the specimens were dried (42° to 50° C.) may have had 

 an injurious effect on the hemolysin, but they do not consider this very probable. 



Recently Usami and Mano {1919) have studied the effects of hookworm extracts on 

 red blood cells. These writers state that hookworm hemolysin is thermostabile, 

 insoluble in water, and soluble in alcohol, ether, and acetone. 



It will be seen from the foregoing summary with reference to hookworm extracts 

 that Loeb and Smith {1904) and Loeb and Fleisher {1910) are the only investigators 

 who failed to observe hemolysis in the presence of these extracts. As will be shown 

 elsewhere in this paper, the negative results of Loeb and Smith may have been due 



