204 DISEASES OF THE DOMESTIC ANIMALS 



age. An incision is made directly over the rib and the rib is then 

 denuded of periosteum by an elevator and three inches or so of rib 

 removed by bone forceps, without penetrating the pleura. The 

 pleura is then incised and the incision extended with the hand. 

 Care must be taken in denuding the rib not to injure the artery just 

 behind the rib. Partial general anesthesia is required for the opera- 

 tion and all adhesions of the lung to the pleura must be broken with 

 the hands. Under partial anesthesia, coughing causes expansion of 

 the lung, whereas if much hemorrhage occurs complete anesthesia 

 will induce collapse of the lung and arrest of bleeding. If the lung 

 can thus be made to expand by breaking all adhesions it will not be 

 necessary to resect more of the ribs than is necessary for manipula- 

 tion, as the expanding lung will fill the pus cavity. The wound is 

 closed, save for a large drainage tube, and irrigation is unwise, 

 except with foul effusion, and then 1-2,000 permanganate solution 

 may be employed. 



Incision and drainage may cure some recent cases without rib 

 resection. 



Pleuro-Pneumonia of Cattle. 



This is an infectious disease often beginning sporadically but 

 becoming enzootic or epizootic. It is transmitted from animal to 

 animal, supposedly, through the expired air for some distance, and 

 also by means of attendants, utensils, infected premises, etc. In- 

 fection is spread by mild cases which have apparently recovered, and 

 also by convalescents, as the infection may persist over a year in a 

 patient. The loss from deaths and imperfect recoveries is from 50 

 to 70 per cent. Incubation period lasts from three to six weeks and 

 the development of the disease is often insidious with increasing 

 cough and diminishing appetite, rumination and lactation, and 

 tenderness on pressure over the ribs, while the temperature is gen- 

 erally above 102 and as high as 104° F. This may last for a month 

 and some apparently recover. The more active stage supervenes 



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