208 CLINICAL VETKRINARV MEDICIXK AND SURGERY. 



sure became negative. Despite these successive modifications the 

 operation always entailed risk until the introduction of antisepsis. 

 Though it produced momentary improvement it was often followed by 

 aggravation of the disease, the pleuritic exudate becoming purulent, 

 and patients dying of emp}-ema. 



Thanks to antisepsis, and possibl}- in some degree to the invention 

 of M. Dieulafoy's aspirator, thoracentesis has become a comparatively 

 innocent operation. Even without an aspirator the operation can be 

 perfectly well performed, provided a slender trocar be used and anti- 

 sepsis observed. The seat of operation having been shaved and dis- 

 infected, the trocar, covered by its cannula, is introduced at the lower 

 part of the seventh or eighth intercostal space close to the spur vein ; 

 the trocar is next withdrawn, allowing the liquid to escape, after 

 which the cannula is removed and the little cutaneous wound covered 

 with a layer of iodoform or sublimate collodion. This constitutes the 

 entire operation. 



With the aspirator the wound in the thoracic wall and the danger 

 of infecting the serous membrane are reduced to a minimum. The 

 taps at the base of the aspirator are first closed, and the air exhausted 

 from the barrel. A rubber tube, pro\ided at its free end with a fine 

 hollow needle previously sterilised b}- immersion in a disinfectant, or b)- 

 passage through the flame, is then slipped over one of the aspirator 

 nozzles. The skin having been prepared the needle is passed into the 

 intercostal space at the point chosen, and the lower tap of the aspirator 

 opened. The needle is then pushed forward until it enters the thoracic 

 cavity. Under the influence of the vacuum in the aspirator, liquid 

 rushes rapidly into the barrel. Exudate may thus be removed in a 

 very short time, but it is better to proceed somewhat slowh-. When 

 the liquid contains fibrous clots the needle becomes blocked from time 

 to time, but a little pressure on the piston expels the fragments, and the 

 flow recommences. 



It is not necessar}' to remo^■e all the exuded liquid, as has been 

 recommended b}- some. Four to twelve quarts are usuall}- sufficient, 

 depending on the size of the animal and the amount of exudate. 

 Puncture may afterwards be repeated if necessary. Unless very 

 abundant, the remainder of the exudate becomes absorbed sponta- 

 neousl}-. 



Resorption is fa\oured b}- administering alkalies, diuretics, or certain 

 drugs which, like arecoline or pilocarpine, stimulate secretion. Last 

 year you saw in hospital a horse with pleurisy following pneumonia, 

 which was only tapped once, one month after the pleuritic affection 

 had appeared, and was afterwards treated by alkalies and hypodermic 



