82 Dr Stone on the Frontal Sinus. 



in Bhurtpore, subsequently a westerly direction into Meywar, 

 where they are deflected towards the south ; again following a 

 westerly direction on the borders of Guzerat, and eventually 

 stretching north on the western side of the Aravulli plateau, 

 where they are perceived to form a continuous series with the 

 rocks which skirt the Rajpootana formations, to the north of 

 Jeypoor and Aymeer. . 



I am sorry that, in this communication, I have been obliged 

 to leave so much to conjecture. To complete a geological sur- 

 vey, with any degree of minuteness, requires the undivided at- 

 tention of the observer, and infers the power of travelling in 

 whatever direction may be deemed necessary for the determina- 

 tion of doubtful points. A public servant, who has other avo- 

 cations, must be satisfied with the few observations which he 

 may be enabled to make in the neighbourhood of the line of 

 route, which his duty compels him to follow. 



On the Fro7itcd Sinus. By Thomas Stone, M. D. (Commu- 

 nicated by the Author.)* 



In this memoir I propose communicating to the Society the 

 general results of my observations concerning the mode of for- 

 mation, average extent, and peculiarities, which characterize. the 

 frontal sinuses in the human cranium ; and when we consider 

 the influence which their development has over the configura- 

 tion, not only of th^ cranial, but also of the facial bones, we 

 shall attach due interest to. every investigation into their history. 

 With the existence of these sinuses the older anatomists, at 

 least those who immediately succeeded Galen, were not unac- 

 quainted, for they were described by Columbus, and Laurentius 

 points them out as demanding especially the consideration of the 

 operating surgeon. It need scarcely be observed, that Vesalius, 

 Albinus, Paaw, Winslow, Cheselden, Monro, and other dis- 

 tinguished anatomists, have likewise described them : but with 

 reference to their origin, they state only, in general terms, that 

 they arise from the diploe having, where they exist, become ex- 



* Read before the Royal Medical Society, March 1831. 



