92 



can only be produced by the specific organisms of tlie 

 disease. It is undoubtedly true that unfavorable in 

 tluences, si'cli as those that cause colds predispose 

 poultry to roup and place the birds iu such a condition 

 that they are more apt to develop it when exposed to 

 it, and perhaps cause the appearance of the disease iu 

 a severe and fatal form when it would have followed a 

 mild course if these unfavorable conditions had not ex 

 isted. Young fowls, tender breeds, and birds in poor 

 condition, and especially those that are poorly cared 

 for, are most predisjiosed to roup. All varities of do- 

 mestic fowls may contract it. It also affects cage 

 birds and outbreaks have been de.soribed among wild 

 birds. 



The characteristic symptom from wluch this disease 

 derives its name consists in the appearance of white 

 patches on llie membrane lining the mouth and nose, 

 the air passages; and these same patclies occasionally 

 develop on the skin, in the intestines or in the lungs. 

 The patches or ronp are at first white and resemble a 

 white mould. The size of the patch is indefinite and 

 never the same in two individuals. It may be ver^' 

 small, or it may extend over Ihe entire lining mem- 

 brane of the mouth. Sometimes, it appears first cm 

 the sides of the tongue, sometimes on the roof of the 

 mouth, sometimes in the throat or about, or in. the 

 nose or eye, on the skin c)f the head, or in the deeper 

 parts of the body. At first, the fowl does not show 

 much inconvenience. As tlie patcli Tnadues it be 

 comes yellow, its borders dry and adhere closely to 

 the mucous membrane, and if it is large enough, it 

 may obstruct the air passages or the mO'Uth and cause 

 serious difficulty in breathing. At this stage of the 

 disease the fowl refuses food, becomes sluggish and 



