DISEASES OF POUI<TRY. 



33 



with the orbital space or cavity surrounding the eyes. 

 The orbital space in birds is relatively very large and 

 has an angular projection towards the point of the beak. 

 There is, consequently, considerable space between the 

 eye -ball and the bony walls surrounding it, which is 

 known as the orbital space or orbital sinus. This 

 space is lined with a mucous membrane which is con - 

 tinuous with that of the nostrils and in such close rela- 

 tions with it that an inflammatory process readily ex - 

 tends from one to the other. Very often in roup, this 

 membrane is inflamed throughout these passages, and 

 the process is so acute that the surface becomes eroded 

 and ulcerated. The secretion, instead of remaining 



fluid as in simple ca- 

 tarrh, changes at this 

 period, is abundant, 

 thick, yellowish pu- 

 rulent, and cheesy. 

 This secretion ac- 

 cumulates and ob- 

 structs the passages. 

 It forms around the 

 eye and forces the 

 eye -ball out of the 

 socket and at the 

 same time collects 

 under the eyelids or 

 on the corner, some- 

 times simulating a 

 false membrane. It, also, plugs the nasal passages, 

 presses down the palate, obstructs the breathing and 

 may prevent swallowing. 



The affected birds in the advanced stages of the 

 disease present a most miserable appearence. The 



Fig. 2.- 



-Head of bird affected with 

 contagious catarrh. 



