41 8 Journal of Agricultural Research voi. xxn, no. 8 



normal serum. The worm material from which the alcohol-soluble sub- 

 stance had been removed was dried and pulverized. A portion of this 

 powder was added to washed sheep corpuscles but failed to produce any 

 hemolytic effect, showing that the hemolytic substances of Bustomum 

 phlehotomum are completely soluble in alcohol. 



In a few experiments the effect of normal serum was tested with a 

 view of determining when it contained bodies capable of inhibiting the 

 action of Bustomum phlehotomum hemolysin. Washed rabbit corpuscles, 

 belonging to a lot that were rapidly hemolyzed by a small quantity of 

 the powder, resisted hemolysis in the presence of a few drops of normal 

 rabbit serum. 



The effect of heat on the hemolysin was found to be the same as the 

 effect of heat on Ancylostoma canimim hemolysin. A salt-solution 

 extract of fresh worms was completely inactivated by heating it for 40 

 minutes at 60° C. 



IX. EXPERIMENTS ON THE POSSIBLE PRESENCE OF ANTICOAGUUNS 



IN HOOKWORMS 



A series of experiments was performed with a view of determining 

 whether the two species of hookworms discussed in the foregoing pages 

 (Ancylostoma caninum and Bustomum phlehotomum) secrete a substance 

 that has the power of inhibiting the coagulation of rabbit blood. Salt- 

 solution extracts of fresh and dried material from the two species were 

 tested as follows. 



Into a series of tubes containing varying doses of extract, rabbit 

 blood drawn directly from the marginal ear vein was allowed to drop. 

 Bach experiment was controlled by allowing an equal quantity of blood 

 to drop into tubes containing physiological salt solution. So far as the 

 rapidity of coagulation of the blood was concerned, appreciable but not 

 very marked differences were detected between the test and control 

 tubes. These experiments were performed on the blood of several 

 rabbits with uniformly negative results. 



Inasmuch as Loeb and his collaborators tested the anticoagulin from 

 Ancylostoma caninum on dog blood and obtained positive results, it would 

 appear that the writer's negative results may indicate that the anticoag- 

 ulins in hookworms are either strictly specific for the blood of their host 

 or that they are perhaps only relatively specific. Further data bearing 

 on hookworm anticoagulin as well as anticoagulins from other nematodes 

 are given in a separate paper (Schwartz, 1921). 



X. EXPERIMENTS WITH EXTRACTS OF HAEMONCHUS CONTORTUS 



Haemonchosis or stomach- worm disease is a disease of cattle and sheep 

 due to the presence in the fourth stomach of a nematode parasite known 

 as Haemonchus contortu^. Young animals are especially susceptible to 



