"Worms in the Intestinal Tract. 463 



gering ; they have cliill eyes at the end of the first day ; open their hill 

 wide and succumb after being sick one day ; occasionally almost imme- 

 diately after the onset of the first symptoms. 



For prophylactic purposes the sick animals should be killed and 

 ducks and geese ought to be kept away from the suspicious water. Dur- 

 ing the months of June and September the latter is usually yellowish 

 or brownish due to the presence of numerous small crabs. 



Rust saw an enzootic among young ducks, infected in their glandu- 

 lar stomach with Tropisurus fissispinus (Tropidocerca fissispina) ; the 

 parasites had produced ulcerative changes of the gastric mucosa. The 

 infection had been produced likewise by Daphnia pulex. 



Freese saw disease in young geese due to the presence of Strongylus 

 nodularis under the mucosa, less frequently in the dark-broAvnish epi- 

 thelial covering of the muscular stomach. The disease manifested itself 

 in progressive emaciation and feebleness in spite of good appetite, and 

 ended fatally within three to eight days. Some few species of this par- 

 asite are frequently found in otherwise healthy geese. 



Literature. Freese, D. t. W., 1908, 713.— Hamann, Cbl. f. Bact., 189.3, XIV, 

 5.55.— Nicolas, J. vet., 1904, 136.— Eust, Pr. VI., 1905, II, 30.— Sturhan, Z. f, Vk., 

 1903, 131.— Wolffhiigel, Z. f. Flhyg., 1903, XIV, 13. 



29. Worms in the Intestinal Tract. Helminthiasis. 



Worms parasitic in tlie intestinal tract produce disease in 

 a variety of ways. 



Contact with the mucosa, adhesion to it, boring into it, pro- 

 duce an irritation, which, according- to tlie number of ^vorms, 

 may cause a circumscribed or a diffuse catarrh or even an in- 

 tense inflammation. Worms armed with hooks may penetrate 

 more deeply into the mucosa ; they may even perforate the in- 

 testinal wall and cause fatal peritonitis. 



Great numbers of larger worms may unite in lumps and 

 may narrow or obstruct the intestinal lumen. On the other 

 hand individual worms may penetrate into a duct opening into 

 the intestines, especially into the bile duct ; they may occlude it 

 and prevent the discharge of a secretion or excretion ; they may 

 exceptionally get from the intestine into the stomach, esophagus, 

 pharynx, buccal cavity or larynx. 



By withdrawal of nutritive material intestinal worms, 

 when present in larger numbers, cause emaciation, eventually 

 also anemia of the host ; in the production of the latter the 

 toxins (leucomaines or ptomaines [Linstow]) of the w^orms 

 play an important role. 



Poisonous substances have been demonstrated in many helminthes. They pro- 

 duce destruction of the red blood corpuscles, reduction of hemoglobin, anemia with 

 poikiloeytosis, the appearance of nucleated red blood corpuscles, including megalo- 

 blasts and an eosinophilia of the blood. They also produce an increased decomposi- 

 tion of the proteids of other organs. 



Many intestinal parasites may bring about secondary in- 

 fections in consequence of injury to the mucosa. Such secondary 



