MORBID ANATOMY 493 



From the observations thus far made the provisonal 

 theory is entertained that the three forms of the exudate — 

 serous or muco-purulent, diphtheritic and sloughed mass — 

 represent three stages in the course of the same disease. It is 

 easily understood that fowls examined in the first stage would 

 be said to be affected with a catarrhal condition of the mucosae 

 of the eyes or nares. It is highly probable that in many cases 

 the disease never reaches the second stage and if these cases 

 alone were examined the diphtheritic condition would not be 



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■i A 'I* 

 It* I' 



k . / 

 Fig. 119. A longitudinal sec- 

 FiG. 118 Diphtheritic exu- tion through the larynx and 



date in the larynx of a fowl : trachea of a fowl {same as 1 18) , 



(a) the grayish-white exudate showing the exudate: [a) in the 



projecting from the glottis. larynx and (6 ) in the trachea. 



suspected. It appears, however, that in the majority of cases 

 the disease runs its course and membranes are formed, slough 

 and recovery follows. It is furthermore presumable that the 

 disease in question appears sometimes in a virulent and de- 

 structive form. I am in possession of statements from poultry 

 raisers which show that there are occasionally epizootics of a 

 disease characterized by exudates in the eyes, nose or mouth, 



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