ETIOLOGY 381 



through the bile ducts into the intestine. Another way of 

 dissemination is in the death of the diseased turkey and the 

 dissolution of its body, whereby the organisms are set free. 



The occurrence of amebse in intestinal affections of man 

 was noticed by Losch in 1875. Since that time it has been the 

 subject of many investigations. 



The points of analogy between the avian and the human 

 disease are that in both there is an affection of the intestine 

 (large intestine in man, ceca in turkeys) associated with liver 

 disease due to amebse. 



The intestinal wall in amebic dysentery is greatly thick- 

 ened, owing to an edematous condition. It is also thickened 

 in circumscribed areas and contains cavities filled with gela- 

 tinous-looking pus. The amebse var}' much in size and con- 

 tain vacuoles. They are found in variable numbers in the 

 bottom of the ulcers and in the discharges. The large num- 

 bers of amebse found in the intestinal contents led Councilman 

 and Lafieur to infer an active multiplication therein. The 

 presence of the parasites within the submucosa is described by 

 these authors in one case only. 



In the turkey, the parasites are always present in the 

 connective tissue spaces of the mucous and submucous mem- 

 brane. Their presence in the contents of the cecum is highly 

 probable. 



It differs from the Ameba dysenteric in being quite uni- 

 form in appearance, varying but slightly in size (from 6 to 

 lOyU in diameter) and in being free from vacuoles. Move- 

 ments characterized as ameboid have not yet been demon- 

 strated. 



The liver affection in man appears usually as an abscess. 

 In turkeys it appears as a variable number of foci in which 

 the microparasites may be present in great abundance. The 

 difference in the nature of the lesions must be largely attri- 

 buted to the different reaction of the tissues of birds toward 

 injuries. 



§ 300. Symptoms. Diarrhea is the symptom which 

 sooner or later may be expected to appear. It probably occu- 



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