TAPPING THE CHEST. 501 



glands, removal is more difficult. When convinced that these glands 

 were implicated, Moller has repeatedly excised them without particular 

 trouble or danger. The " heat bumps " require the animal to be 

 kept from work, or the collar to be eased. Moist warmth favours 

 their subsidence. Those suppurating must be opened early and 

 thoroughly disinfected. 



VIII.— TAPPING THE CHEST (PARACENTESIS THORACIS). 



This operation, practised in man since the earliest times, was 

 first introduced into veterinary surgery by Lafosse in 1772. It 

 is adopted to remove fluid, especially pleuritic effusion, seldom to 

 get rid of air. The diagnosis of such conditions is explained in the 

 text-books on special pathology, and can usually be determined 

 without the explorateur. In detecting empyema, however, the 

 exploring needle is serviceable. Pleuritic effusions compress the 

 lungs and diaphragm, and, interfering with respiratory movements, 

 and the heart and great vessels, impair circulation. Tapping relieves 

 these untoward conditions, but does not always arrest outpouring 

 of fluid or save life. Hence the operation is sometimes regarded 

 as an experiment, though it is often performed. Its timely adoption 

 is frequently useful in hydrothorax following acute pleurisy, though 

 seldom in cases of empyema. No permanent benefit results from 

 removing blood from the pleural sac, because if the membrane is 

 not seriously diseased absorption rapidly occurs. In perforating 

 wounds of the chest, the early injection of antiseptics and performance 

 of paracentesis may sometimes prevent injurious effects from de- 

 composition of the exudate. 



(1.) Puncture of the Thorax for Removal of Pleuritic 

 Exudate. — The trocar used for the larger animals has a diameter 

 of I inch ; but one of smaller calibre is usually preferable. Side 

 openings in the cannula are not of particular value. Various pre- 

 cautions require to be observed : — ■ 



(1) Carefully disinfect the instrument and site of operation. 



(2) Prevent entrance of air into the thorax. 



(3) Remove contents slowly, to minimise interference with 



circulation. 



The patient, if possible, should stand, as the recumbent position 



only adds to the difficulty of the operation. This applies equally 



to the smaller animals, especially if there is much dyspnoea. Dogs 



with hydrothorax sometimes die in a few minutes from being placed 



