488 DIPHTHERIA IN FOWLS 
lesions in most cases. The cause of death and the extreme emaciation 
are difficult to explain in those cases where the lesions are confined to 
one eye or to the mucosa of the nares, excepting on the supposition 
that some poisonous or toxic substance was absorbed. In those cases 
where the lesions are in both eyes, or in the mouth and throat, diffi- 
culty in finding or swallowing food affords a rational explanation. 
In some cases the exudate is of a croupous character, in others of a 
diphtheritic nature. Three stages or varieties of lesions, which repre- 
sent the types of this disease as encountered in this country, may be 
more definitely defined as follows: 
An exudate of a serous or muco-purulent character in the con- 
junctiva and nasal cavities. Ordinarily this condition cannot be 
recognized in the mouth. The mucosa in these cases is apparently 
but slightly altered. 
The mucosa over a small or larger area is covered with a spreading 
exudate of a grayish or yellowish color. It is firmly attached to the 
mucous membrane and when removed leaves a raw, bleeding surface. 
Sections through this exudate and the subjacent tissues show that the 
epithelial layer is destroyed and the underlying tissue infiltrated with 
cells. The extent of the infiltration varies in different individuals. 
The mucosa is covered with a thick mass of exudate, varying in 
color from a milky white to a lemon yellow or brown. It is easily 
removed, leaving a more or less granular 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 margins prevents the fowl from expelling the exudate after it 
becomes 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, may be summarized as follows: 
Abnormal conditions, representing the intermediate and connecting 
links between the types of lesions, are frequently encountered. 
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 mucosa of the mouth are 
areas of diphtheritic exudate. 
