242 INFECTIVE DISEASES. 



limited almost entirely to the lungs ; congestion is quickly followed 

 by inflammation and effusion into the air vesicles and the intra- 

 lobular fibrous tissue which is so well marked in the lungs of cattle. 

 Leucocytes are entangled in the fibrinous lymph, and the intra- 

 lobular septa are enormously enlarged, so that the red lobules are 

 mapped out by the paler septa, and produce on section of the diseased 

 parts a very striking marbled appearance. A somewhat similar 

 appearance is sometimes observed in septic pleuro-pneumonia in 

 calves. The effusion occurs also in the air vesicles. The stages 

 of grey hepatisation and suppurative softening have not, as a rule, 

 time to develop. Hsemorrhagic infarctions are sometimes produced, 

 which in turn become gangrenous or cheesy, and a capsule may form 

 round the diseased part. Roy found micro-organisms in the lymph, 

 but attached no importance to them. Bruylants and Yerriet also 

 described a micro-organism in the lymph. Later, Poels and Nolen 

 isolated a micrococcus resembling JFriedlander's pneumococcus. 

 Inoculation in the lungs produced a condition in cattle which they 

 considered indicative of pleuro-pneumonia. 



Lustig was unable to confirm these observations, but succeeded 

 in isolating from lymph a bacillus and three species of micrococci. 

 One of the micrococci formed an orange growth when cultivated, 

 and was regarded as the specific micro-organism, as it caused sub- 

 cutaneous tumefaction, and, it is said, some degree of immunity. 



Brown cultivated a number of organisms which on inoculation 

 only produced local irritation. Intravenous injection produced death 

 from septicaemia in one case in thirty-six hours. 



Arloiiig isolated four different organisms, including a bacillus 

 which was named Pneumo-bacillus liquefaciens bovis. Later, he 

 prepared a fluid from broth- cultures, pneumo-bacillin, which pro- 

 duced a more marked rise in temperature in animals suffering from 

 pleuro-pneumonia than in healthy animals, and its use was 

 suggested as an aid in diagnosis. Arloing named the micro- 

 organisms provisionally Pneumo-bacillus liquefaciens bovis, Pneumo- 

 coccus gutta cerei, Pneumococcus lichenoides, and Piieumococcus 

 flavescens. 



Pneumo-bacillus liquefaciens bovis. Short rods, non- 

 motile ; spore-formation not observed. They rapidly liquefy gelatine, 

 and form on potato a white layer, which becomes brownish and 

 sometimes greenish. According to Arloing pure-cultures produce 

 in the ox, when injected subcutaneously or in the lung, the same 

 lesions which are produced by virulent lymph. Guinea-pigs and 

 rabbits are slightly susceptible, dogs are immune. 



