Nov. 19, i92t Hemotoxins from Parasitic Worms 419 



stomach-worm disease, and among other symptoms they show those of 

 a rather severe anemia. As in hookworm disease, the direct abstraction 

 of blood by the parasites undoubtedly plays a part in bringing about the 

 train of morbid symptoms associated with loss of blood, but that other 

 factors are involved — ^namely, a chronic intoxication of the host by toxic 

 substances liberated by the parasites — appears probable. Furthermore, 

 it is by no means unlikely that as the suceptible animals grow older they 

 become more or less immune to the effects of the parasites, although they 

 are by no means immune to infestation with the worms. Whether the 

 immunity is developed as a result of a previous infestation or whether 

 it is a natural immunity associated with maturity is not known. In fact 

 the clinical phase of haemonchosis is still an almost unexplored field in 

 parasitology. 



The following experiments were performed by the present writer with 

 reference to the presence of a soluble hemotoxin in this parasite. 



A number of specimens of Haemonchus contortus (about 100) that had 

 been removed from a calf shortly after death were washed a number of 

 times in physiological salt solution and kept in a refrigerator overnight. 

 The following day the specimens were still alive. They were ground up 

 in a mortar with a small quantity of physiological salt solution. The 

 crushed material was transferred to a test tube and allowed to remain at 

 room temperature for about two hours. The supernatant fluid was then 

 tested on a 5 per cent suspension of washed sheep corpuscles. After 

 2 hours at 37° C. a number of tubes containing graded quantities of 

 extracts and 5 drops of washed red blood cells showed no trace of 

 hemolysis. The tubes were then transferred to a refrigerator, where they 

 remained 18 hours longer. A faint trace of hemolysis was present in 

 the tube containing the largest quantity of extract. The control tube 

 was intact. 



A second experiment of a similar nature was performed with another 

 lot of fresh worms. In this case the extract was tested on washed 

 sheep blood corpuscles, with negative results. Alcoholic specimens of 

 Haemonchus contortus from sheep were washed in salt solution to re- 

 move traces of the alcohol and then dried at 37° C. The dried mate- 

 rial was pulverized, and part of it was extracted in salt solution and 

 tested on washed sheep corpuscles, with negative results. The remain- 

 ing portion of the dried material was extracted in 95 per cent alcohol 

 and the extract suspended in salt solution. Tested on sheep corpuscles, 

 this extract likewise yielded negative results. 



A number of fresh specimens of Haemonchus contortus were dried at 

 37° C. and pulverized in a mortar. Graded quantities of the powder 

 were added to washed sheep blood corpuscles. After 2 hours at 37° 

 followed by 18 hours in a refrigerator slight hemolysis was produced. 



