506 TAPPING THE PERICARDIUM IN THE DOG. 



terminate in recovery, the exudate becoming reabsorbed, the symptoms 

 gradually diminishing and finally disappearing. In certain cases it 

 assumes the chronic form. 



In general, when the veterinary surgeon is called on to examine 

 a dog affected with exudative pericarditis, the disease has already 

 been in existence for some time, occasionally for several weeks ; 

 and, provided he makes a complete examination of the patient, and 

 does not forget the heart, a careful consideration of the signs fur- 

 nished by palpation, percussion, and auscultation should enable 

 him to arrive at a correct diagnosis. Ascites is often the most striking 

 symptom, and puts one on the right path. It is usually easy to 

 differentiate between pericarditis and pleurisy. In pleurisy with 

 moderate exudation, resembling that of pericarditis, the zone of 

 dulness changes with the animal's position. By standing the animal 

 on its hind legs the heart-sounds and vesicular murmur become 

 readily perceptible, while the upper part of the thorax is resonant ; 

 in the normal standing position the resonance disappears or becomes 

 dulled. 



When, despite treatment, the exudate increases and the symptoms 

 become more marked and alarming, or when even on first examination 

 the general condition appears dangerous, the pericardium can be 

 punctured. 



Operation is as follows : — -The precordial region is prepared by 

 clipping away the hair, and shaving the skin a little below the centre 

 of the zone of dulness for a distance of two or three square inches. 

 The parts are afterwards washed with alcohol, and with a "1 per 

 cent, solution of sublimate. The aspirator is provided with a rubber 

 tube. The air being exhausted from the cylinder of the aspirator, 

 the instrument is passed to an assistant ; the point of the needle 

 is then introduced at the centre of the prepared surface, through 

 the fifth intercostal space three or four fingers' breadth above the 

 lower margin of the thorax. As soon as its end has fairly entered 

 the thoracic wall the tap connected with the aspirator is opened 

 and the needle very gently pushed forward until liquid appears in 

 the glass index of the rubber tube. Operating in this way the needle 

 need only just enter the pericardium, and with a short point, injury 

 of the heart, which is always pushed upwards, need not be feared. 

 Furthermore, by using a small needle, fluid is very slowly withdrawn 

 and danger of syncope prevented. In the absence of an aspirator, 

 puncture may be effected with a fine trocar. The injection of warm 

 1 per cent, boric acid solution or normal salt solution has been sug- 

 gested after withdrawal of the fluid contents of the sac, but is difficult 



