426 Journal of Agricultural Research voUxxn.No. s 



CEsophagostomum yielded similar results. In another paper Weinberg 

 {1909) records that the injection of extracts of worms of the genus 

 Strongylus into guinea pigs leads to a pigmentation of the spleen but seldom 

 of the liver. From this, it appears that erythrocyte destruction takes 

 place in animals that harbor hemotoxin-producing parasitic worms and 

 that the disintegration products of the erythrocytes are ingested by 

 leucocytes, arrested in certain organs, and eliminated through the 

 excretory system. 



Whether the hemotoxic substances from parasitic worms are liberated 

 during the normal life of the worms, or whether they are liberated only 

 when worms sicken or degenerate, as appears to be the case in Diphyllo- 

 bothrium latum, can not as yet be stated with certainty. In the case of 

 D. latum the view that only certain specimens secrete the hemolysin has 

 been advanced by a number of investigators, especially by Leichten- 

 stern (1896). Tallqvist's experiments show that hemolysins are present 

 in specimens of D. latum expelled from patients that show no symptoms 

 of anemia as well as in specimens obtained from cases of severe anemia. 

 Tallqvist's hypothesis that the hemolysin is eliminated when the worms 

 disintegrate finds confirmation in numerous cases in which eggs of 

 D. latum are present in the feces of patients, and anthelmintic medication 

 fails to expel any worms and merely yields a mass of eggs. Another 

 factor which may be of importance, and which, so far as the present 

 writer is aware, has been entirely overlooked, is the fact that certain 

 individuals may lack antilytic constituents in their blood and are thus 

 susceptible to the toxin which other individuals are capable of neutralizing. 

 That the antilytic properties of the blood may under certain conditions 

 be absent is probable from the observations of Noc {1908) with reference 

 to hookworm disease. Whether the observations with reference to D. 

 latum are applicable to other parasitic worms, especially to nematodes, 

 can not in the light of our present knowledge be stated with any degree 

 of certainty. That parasites may die in the intestine or other location 

 and disintegrate before they are eliminated from the body of the host 

 is by no means improbable. Cultures of larvae of parasitic worms in 

 vitro show that bacteria may kill the worms, and that the latter undergo 

 degenerative changes,- such as complete internal disorganization, quite 

 rapidly. That worms may be attacked by bacteria and other organisms 

 in the body of the host is by no means improbable. Weinberg has in 

 fact described what appears to be a disease in worms belonging to the 

 genus Ascaris, which is characterized by the presence of certain pig- 

 mented spots that are clearly visible through the cuticle. The present 

 writer has observed this condition in specimens of Ascaris lumhricoides 

 on several occasions. 



Whether parasitic worms liberate their toxic secretions during life or 

 whether these substances partake of the nature of endotoxins and are 

 not liberated from the bodies of the worms unless the latter disintegrate 



