256 Journal of Agricultural Research voi. xvi. no. 9 



while in other cases they show evidences of suffering from such infestation 

 may perhaps be explained in much the same way as the differences 

 observed in cases of infestation with Dibothriocephalus. 



The inhibitory effect of the serum on the hemolytic action of the body 

 fluids and extracts of the worms appears to be a direct negation of the 

 view that anemia of animals harboring ascarids is due to the toxic secre- 

 tions of the worms. It is necessary to remember, however, that a reac- 

 tion in vivo may be very different from a reaction in vitro. 



Apart from the question of anemia as a result of the absorption of toxins 

 produced by Ascaris, there is the question of anemia as a result of the 

 direct abstraction of blood by the parasite. The opinion that Ascaris is a 

 bloodsucker has been expressed by Schimmelpfennig (p), who based his 

 view largely on the fact that the body fluid of ascaris contains oxyhemo- 

 globin, the source of which presumably is the blood of its host. The view 

 that Ascaris may suck blood is also supported by the structure of the 

 mouth parts of the parasite and the lesions observed in the mucosa of 

 intestines of animals harboring ascaris. 



It should be remembered that ascaris is provided with strong chitinous 

 lips, denticulated along their edges. That such buccal armature could 

 succeed in lacerating the smaller blood vessels of the intestine is by no 

 means improbable. Blanchard {2) states that there can be no doubt that 

 A. lumbricoides bites the intestinal mucosa. Guiart (7) has shown that 

 A. conocephala is often firmly attached to the mucosa of its host; he also 

 states that Leroux found wounds in the intestinal mucosa of man resem- 

 bling punctures which were apparently produced by A. lumbricoides. 



Friedberger and Frohner (6) state that the intestinal mucosa of dogs 

 harboring ascarids often shows evidence of punctures. 



The above obser\''ations, coupled with the presence of oxyhemoglobin 

 in the worms, a substance which apparently is constantly being excreted 

 by the parasites (to judge from their behavior in vitro) and which conse- 

 quently must be as constantly renewed, appear to favor the view that 

 Ascaris probably supplements its food intake by sucking blood from time 

 to time. The hemolytic substance which is particularly abundant in the 

 intestine of the worms apparently serves the purpose of liberating the 

 oxyhemoglobin from the corpuscles some of which passes into the body 

 fluid of the parasites. In this connection it should be recalled that Ascaris 

 is rich in iron and that this substance enters in considerable quantity into 

 the composition of the eggs (Schimmelpfennig, 9). The significance of 

 the oxyhemoglobin in the body fluid of the worms is not well understood. 

 "Whether it merely represents a by-product in the metabolism of the worm 

 and is always excreted as such, or whether it may also first be broken 

 down into simpler compounds with the retention of some of the iron by 

 the tissues of the parasite, still remains to be answered. Whether or not 

 oxyhemoglobin fulfills an important function in the life processes of the 

 worm — perhaps in oxidation — is another question to be solved. In this 



