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BULLETIN 260, U. S. DEPARTMENT OF AGRICULTURE. 



of such infestation. Ascarids at times enter the appendix and cause 

 appendicitis ; they may perforate the intestine and cause peritonitis ; 

 they may come up the esophagus and get down the windpipe, with a 

 resultant suffocation, or enter the eustachian tube of the ear. These 

 are unusual cases for the most part, but they are dangers to be con- 

 sidered. There are other unpleasant and dangerous features of 

 ascarid infestation, and the uncomfortable certainty that their pres- 

 ence is undoubtedly indicative of fecal contamination of food, drink, 

 or ingesta of some sort. 



The prophylaxis in this case, as in the case of the previously men- 

 tioned worms, depends on keeping dogs free from worms and restrict- 

 ing their privileges in the household and in their relationship to 

 human beings. 



Fig. 10. — Head of a dog split in half to show three tongueworms (Lingua- 

 tula rhinaria), a, in the nasal cavity. Reduced in size (after Colin). 



Tongueworm. — The tongueworm, Linguatula rhinaria (Linguatula 

 serrata) (fig. 10), occurs in the adult stage in the nasal passages 

 and frontal sinuses of the dog. It is light colored and shows an 

 external, ringlike segmentation. The male may attain a length of 

 20 millimeters (about three-fourths of an inch) and the female may 

 attain a length of 100 millimeters (about 4 inches). The eggs de- 

 posited by the female leave the nostrils of the dog in the catarrhal 

 secretion occasioned by the presence of the parasite, some of them 

 doubtless being sneezed out, and contaminate the vegetation on 

 which they at times lodge. Such vegetation may be eaten by cattle, 

 sheep, horses, or swine, or if the infested dog has access to a truck 

 garden or a family vegetable garden, contaminated lettuce, cabbage, 

 etc., may be eaten by man. When the eggs get to the stomach the 

 shell is digested off, releasing a peculiar embryo which shows by its 

 structure that these tongueworms are really related to the mites, a 

 group of spiderlike animals. This embryo makes its way through 



