ITS SURGICAL AND MECHANICAL TREATMENT. 87 



It is evident that the instruments hitherto 

 described were not only wrong in principle — as (with 

 the exception of the one described by Par6 as kept 

 in by an oblong button) they were kept in place 

 by the pressure of sponge on all sides of the 

 fissure, which we know must have ended in aggra- 

 vating the evil it was intended to overcome — but 

 their adaptation to the roof of the mouth must have 

 been extremely imperfect, as they appear to have 

 been made by a goldsmith without a model of the 

 mouth, and hence the complaint of Guillemeau : — • 

 "There are some which cannot very well suffice 

 themselves with this plate, by reason that the 

 gouldsmith cannot soe conveniently make the same, 

 that it equally of all sides doe touch the palate.'* 

 But we now arrive at a period when a great 

 improvement was effected in these instruments 

 (Plate IX., Figs, a, b, c, d, e, f). M. Pierre Fou- 

 chard, in his treatise, 1786, entitled, "Le Chirur- 

 geon-Dentiste," describes four or five difierent obtu- 

 rators ; and the great improvement in their con- 

 struction over all preceding ones consisted in the 

 mode which he employed for keeping them in their 

 place. Instead of filling up the fissure with sponge, 

 which when moistened would swell and exert pres- 

 sure on the margins of the fissure, he made a con- 

 cavo-convex plate to cover the fissure : to the centre 

 of the convex surface he attached a tube, through 

 which passed a screw, to the superior extremity of 

 which were attached two wings, the inferior extre- 



