MORBID ANATOMY 329 



troyed and the underlying tissue infiltrated with cells. The 

 extent of the infiltration varies in different individuals. 



(3) The mucosa is covered with a thick mass of exu- 

 date, varying in color from a milky white to a lemon yellow 

 or brown. It is easily removed, leaving a more or less granu- 

 lar and healed surface. This sloughed mass is frequently 

 dried at its margins to the adjacent tissue. It emits a strong 

 putrid odor, due to decomposition. The drying of the mar- 

 gins prevents the fowl from expelling the exudate after it be- 

 comes separated from the underlying tissue. 



The evidence to support the supposition that the three 

 forms or types of exudate described are different stages in the 

 same morbid process, as gathered from the post-mortem notes 

 and bacteriological study of the cases investigated, ma)' be 

 summarized as follows. 



(a) Abnormal conditions, representing the intermediate 

 and connecting links between the types of lesions, are fre- 

 quently encountered. 



(d) Although at the time of examination (post-mortem) 

 but one form of exudate is usually present in a single fowl, there 

 are exceptions, in which two and occasionally the three forms 

 are coincident. Thus the eye is covered with a sloughed 

 exudate, the posterior nares contains a layer of muco-purulent 

 substance and on the muco.sa of the mouth are areas of a 

 diphtheritic exudate. 



In fowls which die, the exudates are for the greater part 

 in the advanced stage, although fatal cases occur in which the 

 lesions are restricted to an abnormal quantity of a serous or 

 muco-purulent, more or less viscid, exudate in the conjunctiva 

 or nasal cavities. The best illustration of the diphtheretic 

 process is found in fowls killed for examination in the second 

 stage of the disease. The distribution of the lesions shows 

 that the conjunctiva is most frequently affected. The exudate 

 in the nasal cavities is in some cases undoubtedly the result of 

 the coagulation of the liquid which has passed during the course 

 of the first stage from the conjunctiva through the lachrymal 

 duct into the nares. In certain cases, however, the lesions appear 

 in the nares primarily. Sections of the exudate, with subjacent 



