Le] 
only produce the teftimonies of two of the lateft authors, who 
have enriched the fcience of Surgery by their writings, namely, 
Mr. Pott of London, and Mr. Bell of Edinburgh. * The former 
having ftrongly recommended the trephine in preference to the 
trepan, and + the latter, on the contrary, having given his deci- 
fion in favour of the trepan. Thefe inftruments are too well 
known to require a minute defcription here. I fhall only remark, 
that the trepan is compofed of a circular faw called a crown, 
fixed in a handle, which is turned round like a joiner’s brace, 
with a knob on the upper part, on which the left hand of the 
operator is refted, to keep the inftrument fteady, while the right 
is employed to turn the handle. The trephine has a faw or crown 
of the fame fort, fixed in an immoveable handle, either of wood 
or iron, fomewhat refembling the handle of a carpenter’s augre, 
and is worked by turning it backward and forward with the 
right hand. a 
{ Tur inconveniencies of the trepan muft be obvious to every 
experienced operator, who will often find a difficulty to get 
either himfelf or his patient into a commodious fituation. To 
operate with it, he muft be placed above the patient, efpecially if 
the 
* Pott’s Works, Vol. I. Note in page 125. 
+ Bell's Syftem of Surgery, Vol. III. page 78. 
{ Quia Chirurgus trepanum fepe non recte tenet nec ortoganaliter ponit fuper cra- 
nium ex quo fit, ut uno latere tangat meningem antequam perforaverit alteram hoc 
autem ex eo fepe contingere poteft cum oculus Chirurgi ex alto afpiciens non bene 
poflit videre an trepanum rete ftet nec ne nifi ab aftante medico admoneatur, Tho- 
mas Fienus de Trepano, Tra¢tat. 1, cap. 3. fol. 6. 
