DISEASES OF POULTRY. 35 



lect and continued exposure to the existing causes, but 

 they will not develop into roup unless the contagion of 

 the last named disease is present. 



The exact species of organism which causes roup 

 can not be certainly determined from the investigations 

 so far made. A bacterial organism resembling the 

 bacillus of fowl cholera and that of rabbit septicaemia 

 has been isolated from some outbreaks. Whether this 

 organism or some other form of microscopic life con- 

 stitutes the contagion makes little difference to the 

 practical poultry man. The recognition of the exist- 

 ence of contagion in some form is the most important 

 thing. 



Roup is a contagious disease which is localized upon 

 the mucous membranes of birds. That is, the micro- 

 scopic parasite which causes the disease, develops and 

 multiplies upon and within the mucous membranes of 

 affected birds ; escapes from their bodies with the dis - 

 charge from the nostrils and eyes; soils their feathers, 

 and, also, the litter and other objects about them; 

 when dried it is dissipated throughout the surrounding 

 air in the form of dust by every movement of the bird, 

 or of the soiled objects, and by every breeze that dis- 

 turbs the contaminated surfaces. This dust, contain- 

 ing the germs of the disease, as it floats in the air is 

 drawn into the nostrils with the breath or lodges within 

 the eye. When the germs reach the moist and warm 

 surfaces of the membranes lining the nostrils or eyes, 

 they find favorable conditions for their continued mul- 

 tiplication. They penetrate the membrane, set up irri- 

 tation and inflammation, and as a result of this action 

 there follow catarrh, ulceration and the formation of 

 purulent and cheesy deposits about the head. 



Treatment. — The measures to be adopted for the 



