11 



The eyes were quite normal. The cheesy mass must, in this case, have formed 

 very quicklv, and without being preceded by serous-purulent catarrh. This, 

 however, was the only case in which there was hemorrhagic inflammation. The 

 diseased mucous membranes were, in other cases, always swollen ; but dirty 

 grey, or brownish in color. They were covered with a grey, putrid mass. Sec- 

 tions through the mucous membrane showed the epithelial cells with cloudy, 

 or finely granular, protoplasm. The nuclei were, in most cases, normal ; 

 some were swollen, homogenous, and difficult to stain, excepting one or two 

 extra round central corpuscles, which stained deeply. Many leucocytes were 

 present between the epithelial cells. They were usually rather long in shape, 



Fig-. 9. —Head of fowl 36, 22 days after inoculation with a culture 

 "of the Roup bacillus, ff. Firmly adherent thick diphtheritic 

 nienihrane upon the conjunctiva of the upper eyelid. 



and were found migrating towards the suriace. The sub-mucous tissue showed 

 a numerous increase of leucocytes, and dilated vessels. The leucocytes which 

 migrated to the surface of the mucous membrane became free, and often joined 

 the firm, cheese-like bodies which have been described. As these grew very 

 quickly, they produced various deformities. 



The mucous membrane may disappear entirely, or be changed to a brown- 

 ish tissue of round cells, which are identical with the pyogenous membrane en- 

 closing the cheesy matter in the sub-mucous tissues, etc. In one case (dis- 

 eased hen i), part of the mucous membrane of the nose was dry and necrotic. 

 Tt consisted of a yellowish, dry. crumbly mass, which easily fell away from the 

 cartilage. The latter was itself necrotic. Very often the medial wall of the 

 infra-orbital cavity was absorbed, and then the solid mass of cheesy matter was 

 in direct connection with that in the free nasal cavities. For this reason, the 

 cheesy mass appeared to have grown fast, which, however, was not the case. 



