Diagnosis. 401 



lungs kills guinea pigs, rabbits, and as a rule also calves in 

 1 to 2 days. Nevertheless the diagnosis may prove difficult 

 even by this niethod of examination, as in some subacute cases 

 of hemorrhagic septicemia the lung tissue may contain only a 

 few ovoid bacteria, which are only slightly virulent for rabbits. 



The characteristics given above hold also for the differentiation of 

 septic pleuro-pneumonia of calves caused by bipolar bacilU, from pleuro- 

 pneumonia. 



Tuberculosis may be mistaken both for the early stage and 

 for the chronic form of pleuro-pneumonia. The severe cough, 

 the absence of extensive dullness, bronchial breathing and sensi- 

 tiveness of the thorax, further the normal temperature or only 

 moderate and sometimes remittent fever and the very slow 

 evolution suggest the probability of tuberculosis. The differ- 

 entiation may sometimes be difficult, as tuberculosis may take 

 on an acute character, and in pleuro-pneumonia the course may 

 become chronic after the disappearance of the acute symptoms. 

 Moreover the establishment of tuberculosis, for instance by 

 microscopical examination of the discharges, does not exclude 

 pleuro-pneumonia, as both affections may exist simultaneously 

 in one and the same animal. 



Traumatic pericarditis has in common with pleuro-pneu- 

 monia the sensitiveness of the thorax, the dullness on per- 

 cussion and the difficulty in breathing. The sensitiveness how- 

 ever is mostly confined to the region of the heart, the dullness 

 is bordered by a concave line running downwards and forwards, 

 the heart's action is quite easily disturbed, and besides a venous 

 pulse is sometimes perceptible in the neck, while on the lower 

 chest an edematous swelling is present. If however the lung 

 is simultaneously affected, the differentiation of the affection 

 from pleuro-pneumonia is impossible. 



A genuine croupous pneumonia in which the fully devel- 

 oped clinical picture entirely corresponds with the symptoms 

 of pleuro-pneumonia, could only be suspected when the possi- 

 bility of contagious pleuro-pneumonia appears to be excluded, 

 and when the disease takes a typical course and disappears com- 

 pletely within a short time after a rapid dissolution of the 

 lung infiltration. On autopsy the slight affection of the pleura, 

 and the entirely uniform color of the hepatized portion of the 

 lung are indications of a genuine pneumonia (the cut surface 

 is sometimes marbled even in these cases but not variegated). 



Finally in infected territories chronic bronchial catarrh, 

 catarrhal pneumonia, verminous bronchitis, pneumomycosis, 

 (nasal discharge!), the echinocoecus disease (good nutritive 

 condition, no sensitiveness of the pleura), as Avell as other affec- 

 tions of the lungs, may give rise to suspicion of pleuro-pneu- 

 monia. 



According to Nocard the diagnosis of pleuro-pneumonia may be made with 

 certainty in a short time by the examination of small portions of the lungs or of 



Vol. 1 — 26 



