434 



On effusion 



I do not flatter myfelf with having obtained this objed ; 

 but I think it a duty to communicate to the Ibciety fome 

 ideas which have occurred to me, and by which 1 have 

 been fo happy as to fucceed in a cafe I had an opportunity 

 of attending, in the French hofpital eflabliflied in Phila- 

 delphia. 



In cafes of accumulated blood between the fcull and 

 dura mater, the adhefion which unites them, is deftroyed 

 in the place occupied by the iluid, the colledted matter is 

 circumlcribed in a larger or.fmaller fpace, it expands the du- 

 ra mater, and forming a tumor that opprefles the brain, pro- 

 duces the effe(5ts which require the operation of the trepan. 



In this cafe a fingle opening made in the fcull on one 

 of the points of effufion, is fufficicnt to give vent to the 

 fluid, becaufe the blood prcfled on all fides by the adlion 

 of the brain, quits the place it had collected in, and flows 

 towards the part that oflers a pafl^age. It happens in this 

 cafe, as it does in that where the accumulation exifl:s be- 

 tween the dura and pia mater, that the blood, equally 

 pre'flcd by the brain, runs between thofe two membranes, 

 flows towards the opening by the trepan, and preflTcs the 

 dura mater outward, which indicates to the operator, that 

 this membrane requires incifion, in order to give pafl'age 

 to the collected fluid. 



It is only in the firft caie that the adhefion of the dura 

 mater to the cranium, by retaining the fluid, requires a 

 repetition of the opening, fhould the operator not meet 

 at firfl: with the precife fpot where the fluid is colledled. 



To avoid thefe inconveniences, I propofe in fuch a cafe 

 to deftroy the adhefion which unites tiie dura laiater to the 

 fcull, and eftabliih a communication between the colleded 

 blood and the opening already made by the trepan ; by 

 this means a repetition of trepanning would be avoided, 

 and the operation becoming more eafy might fave the 

 Ufe of the patient in any cafe not necefl^arily mortal, which 



