338 
J. T. DUNCAN. 
DEFINITION. 
It is an insidious, exudative, zymotic disease, due to a specific 
poison or ferment, peculiar to the ox, and having its local mani¬ 
festations concentrated in the lungs and pleura.*— (Walley.) 
PATHOLOGY AND SYMPTOMS.f 
There is much variety in the manifestations of the disease. 
In some instances, more especially during its first outbreak in a 
district, it runs a rapid course, destrojdng life in the course of a 
few days, the lungs after death presenting the appearance of a 
congestive inflammatory change. In other cases—and these are 
far the most numerous—the onset, course, and termination of 
the disease occupy a period of from four to eight weeks, or even 
longer, the animal becoming much emaciated and finally succumb¬ 
ing to an exhausting diarrhoea, imperfect aeration of its blood, 
hydrothorax, or to the depressing influence of degenerated ani¬ 
mal matters in the blood, and ansemia. 
Premonitory Symptoms .—Similar to the cattle plague, the 
commencement of the disease is often not observable. Thus at¬ 
tention is only called in many instances to an animal for the first 
time appearing unwell, but in which an examination brings to 
light the fact that changes of structure have taken place to such 
an extent as to convince the observer that disease has been grad¬ 
ually increasing for a lengthened period. The thermometer is 
the only true guide by which we are able to discover the end of 
the incubative, and the beginning of the active stage. For ex¬ 
ample, the introduction of the disease into Australia from this 
country proves that the first manifestation of illness is not at all to 
be depended upoG as a guide to its true commencement; for the 
carriers of contagion—bulls for breeding purposes—were three 
months on the voyage; the disease only breaking out after they 
were landed. 
It is of great importance that thermometric observation should 
be made during the prevalence of pleuro-pneumonia, in order 
*Professor Yeo questions its zymotic character, 
t From Principles and Practice of Veterinary Medicine. 
