PARACENTESIS TllOllAUlS (tAI'I'ING THE CHEST). 473 



tlic trachea with the thumb and fingers of the left hand, and then a longi- 

 tudinal incision cautiously made through the skin, three inches in length. 

 This is usually effected, "when there is no express indication to the contrar^^, 

 on the fifth and sixth rings ; a slip from which, and the connecting liga- 

 ment above and below, about half the width of each ring, should be excised 

 •with the intervening ligament. The remaining portion will then be strong 

 enough to retain the perfect arched form of the trachea. 



If the orifice is only to be kept open while some foreign body is ex- 

 tracted, or tumour removed, or ulcer healed, or inflammation subdued, 

 nothing more is necessary than to keep the lips of the wound a little apart, 

 by passing some thread through each, and slightly everting them, and 

 tying the threads to the mane. 



If, however, there is any permanent obstruction, a tube will be necessary. 

 It should be two or three inches long, curved at the top, and the external 

 orifice turning downwards with a little ring on each side, by which, through 

 the means of tubes, it may be retained in its situation. 



The purpose of the operation being answered, the flaps of integument 

 must be brought over the wound, the edges, if necessary, diminished, and 

 the parts kept in apposition by a few stitches. The cartilage will be 

 perfectly reproduced, only the rings will be a little thicker and wider. 



The following account will illustrate the use and the danger of the 

 tracheotomy tube. A mare at Alfort had great distortion of the rings of 

 the trachea. She breathed with difficulty. She became a roarer almost 

 to suffocation, and was quite useless. Tracheotomy was effected on the 

 distorted rings, and a short canula introduced. She was so much relieved 

 that she trotted and galloped immediately afterwards without the slightest 

 distress. Six months later she again began to roar. It seemed that the 

 rings were now distoi-ted below the former place. 



M. Barthelemy introduced another canula, seven inches long, and which 

 reached below the new distortion. She was once more relieved. She 

 speedily improved in condition, and regularly drew a cabriolet at the rate 

 of seven or eight miles in the hour ; aud this she continued to do for three 

 years, when the canula became accidentally displaced in the night, and 

 she was foiind dead in the morning. 



PARACENTESIS THORACIS (TAPPING THE CHESt). 



By auscultation and other modes of examination, the existence of effusioii 

 in the chest is ascertained, and, possibly, it is increasijig. Is there any 

 mechanical way of getting rid of it ? There is one to which recourse 

 should be had as soon as it is evident that there is considerable quantity 

 of fluid in the chest. The operation of Paracentesis, or tapping, should be 

 performed ; it is a very simple one. One of the horse's legs being held up, 

 and, counting back from the sternum to between the seventh and eightli 

 ribs, the surgeon should first make a longitudinal incision through the 

 skin, and then pass a moderate-sized trochar into the chest immediately 

 above the cartilages. He will not have selected the most dependent 

 situation, but as near it as he could with safety select ; for there would not 

 have been room between the cartilages if the jDuncture had been lower ; 

 and these would have been injured in the forcing of the instrument be- 

 tween them, or, what is worse, there would have been great hazard of 

 wounding the pericardium, for the apex of the heart rests on the sternum. 

 Through this aperture, close to the cartilages, the far greater part of the 

 fluid may be evacuated. The operator will now withdraw the stilette, 

 and let the fluid run through the canula. He Avill not trouble himself 

 afterwards about the wound ; it will heal readily enough ; perhaps too 

 quickly, for, could it be kept open a few days, it might act as a very useful 



