392 Contagious Pleuro-pneumonia. 



Inoculation of a culture into the pleural cavity produces, after 

 a similar period of incubation, sero-fibrinous pleurisy and peri- 

 tonitis, serous infiltration of the lung tissue and acute swelling 

 of the mediastinal lymph glands. Inhalation of a virulent cul- 

 ture may result in fever and symptoms of bronchial catarrh, 

 which however disappear after 1 to 2 weeks, while animals 

 which are slaughtered in the meantime show serous infiltration 

 of the interstitial connective tissue of the lungs. The feeding 

 of cultures is without effect, likewise intravenous or intra- 

 tracheal injections, provided that none of the culture enters the 

 subcutaneous connective tissue. Intracerebral injections of a 

 few drops of pure culture results in 6 to 14 days in fever, 

 symptoms of cerebral irritation, later apathy and drowsiness, 

 and invariably in inflammation of the joints (experiments of 

 Nocard, Roux & Dujardin-Beaumetz). 



The fluid of the lungs and the pleural exudate of affected 

 cattle possesses a similar pathogenic action, according to the 

 older investigations of Willems. The reactive inflammation 

 however is much less pronounced when the lymph is not injected 

 into the rump or the neck, but in the connective tissue at the 

 point of the tail, which is more tense and has a lower .temperature 

 (such inoculations in sucking calves frequently result in serous 

 or fibrinous inflammations of the joints, and Dschunkowski ob- 

 served similar manifestations from injections into the rump of 

 reindeer). Injections of lung juice into the milk cistern of a cow 

 produces a severe mammitis, which results in recovery after 

 four weeks, but the pus-like, tenacious milk contains the virus 

 even after two months, and its virulence has in the meantime 

 been increased (Nocard). 



Cattle which have recovered from an inoculation disease 

 later resist subcutaneous or intrapleural inoculations without 

 reaction, while by feeding and also by intravenous or intra- 

 ocular inoculations no immunity can be produced. 



Besides cattle and closely related species (buffalo, reindeer, 

 camel, yak, bison) other animals and man are not susceptible 

 to either artificial or natural infections. 



Dujardin-Beaumetz obtained cultures by cultivating the virus on media jire- 

 pared from mutton and from sheep serum, or from goat meat and goat serum, 

 which produced a typical action in cattle, and similarly also in sheep and goats. 

 The effusions produced in cattle, however, were no longer virulent for the last named 

 species of animals. 



The channels for the natural infection are not yet clearly 

 known. In addition to being found in the affected lung tissue, 

 the pleural exudate and the lymph glands of the thoracic cavity, 

 the virus is also present in the bronchial secretions and in the 

 nasal discharge, probably also in the moist exhaled air, and is 

 possibly introduced into the bodies of healthy animals with the 

 inhaled air. Up to the present hoAvever it has not been possible 

 to produce artificially, by inhalation of infectious exudate and 

 secretions or in other ways a disease which completely corre- 



