240 Veterinary Medicine. 



Trasbot), and even sponging the bod 3^ or legs with cold water 

 when heated or fatigued or both. St. Cyr found that pneumonias 

 stood to pleuri.sies as 3 : i , Trashbot as 10 : i , yet the latter draws 

 attention to the fact that in cavalry horses habituated to the stable 

 and sent out into camps in the depth of winter, the pleurisies are 

 more numerous than pneumonias. This may suffice to show the 

 importance of the role filled by cold and chill in the production of 

 pleuris)'. Yet many physicians look upon the chill as a predispo- 

 sition only, while the true origin of disease is microbian. And in 

 man a large proportion of pleurisies appear to be distinctly tuber- 

 culous. Bowditch traced 90 cases of acute pleurisy and found that 

 32 had tuberculosis. The objection to generalizing too largely on 

 this for the lower animals is that the horse and dog, in which tu- 

 berculosis is rare, are by far the most common subjects of pleurisy, 

 whilst cows which are very prone to tuberculosis show few cases 

 of simple pleurisy. Again we find pleurisy in the horse as the re- 

 sult of other diseases localized in or adjacent to the pleura, and 

 where there is nothing to indicate tuberculosis. Thus it follows 

 pneumonia approaching the surface of the lung, cancers, actino- 

 mycosis and other tumors, and traumas— a pulmonary abscess 

 bursting into the pleura, a broken rib scratching and lacerating 

 the lung, a perforating wound of the intercostal space, or in cattle 

 a sharp pointed body advancing from the reticulum toward the 

 heart. 



But the presumptive absence of the tubercle bacillus in the 

 great majority of pleurisies in the horse does not prove the absence 

 of all pathogenic microbes. Trasbot, who rejects the microbian 

 theory, found that the injection of a little of the exudate into the 

 pleural cavity of a sound horse, always determined a generalized 

 pleurisy. Injections of distilled water with the same antiseptic 

 precautions, made separately by himself and lyaborde, had no 

 pathogenic effect. Trasbot attributes the pleurisy vaguely, to the 

 irritant effect of the exudate, but if it should finally be shown that 

 this exudate contains microbes, though they may not be those of 

 tuberculosis, the irritant action will be much more clearly ex- 

 plained. There are forms of pleurisy which are unquestionably 

 the result of microbes, as in lung plague, influenza, canine dis- 

 temper, glanders, tuberculosis, pneumo-enteritis, actinomycosis, 

 and theoretically it might be supposed that in our ordinary acute 



