DISEASES OF POULTRY. 113 



The Trichosoma contortum is a round worm, the 

 male of which is one -half to three -fourths inch in 

 length and the female one and one -fourth to one and 

 one -half inches. It is found in the cervical dilatation 

 of the oesophagus where, according to Railliet and 

 Lucet, it causes in Pekin ducks an engorgement or ob- 

 struction by accumulation of food. This obstruction 

 is analogous to the impacted crop found in fowls and 

 pigeons. 



The disease caused by these parasites has been called 

 the ingluvial indigestion of ducks and has been at- 

 tributed to the food being too dry, or too abundant, or 

 swallowed too hurriedly. The chief factor in causing 

 the disease appears to be this worm, which lives in the 

 walls of the oesophagus, where it bores channels or 

 galleries and weakens the tissues. In examining, 

 after death, the affected birds, the cervical portion of 

 the oesophagus was found enormously distended with 

 food, while its walls were very thin and congested. 

 To the naked eye or through a hand lens the mucous 

 membrane at that part shows white or light yellow 

 lines, sometimes slightly raised above the surface. 

 These lines are found on microscopic examination to 

 be galleries beneath the mucous membrane which 

 have been formed by the worms in their move- 

 ments, and in which these worms and their eggs may be 

 readily seen. As many as thirty of these worms have 

 been found in the oesophagus of one bird. 



The action of this parasite is believed to be mechani- 

 cal. In boring through the walls of the oesophagus, 

 the tissues are weakened, leading to imperfect contrac- 

 tion of the muscular fibres. The food collects in the 

 cervical dilatation, the contractions of the walls are not 

 sufficiently vigorous to force it onward, and dilation 

 with impaction follows. The impacted osspphagus 



