PARACENTESIS THORACIS. 301 



is, to condense the adjacent vesicles, and to make the sides of 

 the vomica, or ulcer, adhere to the inside of the parietes of the 

 thorax, thereby limiting the extent of what may be contained 

 in their cavities. Without this, it is probable air might be let 

 loose into the cavity of the thorax, and might produce the 

 symptoms above ascribed to it. For it is not uncommon to 

 see even pretty large branches of the trachea eroded by matter, 

 by which the air gets into the vomicae or ulcers ; of this my 

 ingenious friend Dr. Stark lately showed me an instance. 

 Whether air has ever thus been let loose into the cavity of the 

 thorax, so as to suffocate the patient, I cannot take upon me 

 to determine. But abscesses of the lungs, with adhesion to the 

 parietes of the thorax, have been known to be attended with 

 the emphysema; of this Palfyn mentions an instance, 1 and 

 Dr. Hunter met with a case of the same kind. In these cases 

 the matter of the abscess had probably eroded the pleura and 

 intercostal muscles, and the air which got from the trachea 

 into the abscess, had escaped through the erosions into the 

 cellular membrane, and had inflated it. 



Although the operation of the paracentesis thoracis is advi- 

 sable in most cases where air is contained in the cavity of the 

 chest ; yet some may be so complicated with other injuries, 

 that the operation, though in itself proper, may yet be unsuc- 

 cessful. But this remark may be unnecessary here, as the 

 same may be made of .every chirurgical operation; and as men 

 of experience will be cautious how they attribute to the remedy 

 that want of success which may be owing to another cause. 



When the operation becomes necessary, the best place for 

 performing it, if the disease is on the right side, will be on the 

 fore-part of the chest, between the fifth and sixth ribs; for there 

 the integuments are thin, and, in the case of air, no depend- 

 ing drain is required. But, if the disease is on the left side, 

 it will be more advisable to make the opening between the 

 seventh and eighth, or eighth and ninth ribs, that we may be 

 sure of avoiding the pericardium. With regard to the size of 

 the wound, it may be proper to observe, that as large pene- 

 trating wounds of the chest are inconvenient on account of the 

 air's entering by the aperture in such a quantity as to prevent 



1 Anatomic Chirurgicale, cap. xx, p. 2. 



