440 FOOT AND MOUTH DISEASE 
hi 
permanent arthritis. It is stated by some authorities that in the 
mild non-fatal cases the obvious lesions are so slight that frequently 
they escape notice. In sheep and swine the lesions are more fre- 
quently restricted to the feet. 
ie Diagnosis. Foot and mouth disease is diagnosed by the symptoms, 
obvious lesions and the inoculation of susceptible animals. It is to be 
differentiated from (a) various forms of stomatitis caused by different 
fungi and often referred to as sporadic aphthz, (b) from stomatitis 
due to drugs and injuries, (c) foot rot or suppurative cellulitis in cattle 
Fic. 103. PHOTOGRAPH SHOWING ULCERS ON THE UPPER GUM. 
and sheep, (d) from actinomycosis of the tongue and (e) from variola. 
It must also be differentiated from simple cellulitis, often of strepto- 
coccic origin, in the subcutaneous tissue about the coronet and from 
the sloughing of the hoof resulting from the extension of the inflamma- 
tory process, and from eczemas due to dietary causes. The means of 
differentiating these must be found largely in the history of the cases 
and in the study of the nature of the lesions themselves. 
The most difficult lesions to distinguish between are certain more or 
less pigmented depressions due to traumatism and foot-and-mouth 
disease lesions rather late in their course. 
