Tod's Anatomy and Physiology of the Organ of Hearing. 377 



"Take the temporal bone of an infant or foetus, and after injecting 

 it, remove all the soft parts from its surface, keeping the membrana 

 tympani entire ; then introduce the point of a small scalpel between 

 the OS annulare and the petrous portion on the under surface, and 

 separate the one gently from the other, so as to raise the two infe- 

 rior thirds of the former about a quarter of an inch from the latter, 

 and put a small piece of wood between them until the parts become 

 quite dry. The different parts will tiien remain permanently in situ, 

 onlj' a little on the stretch. Again, talce another temporal bone of 

 the same age, and gradually remove the osseous shell which forms 

 the upper part of the fossa navicularis, and the inferior part of the 

 cavitas tympani, and put the preparation aside to dry. Evcrj' tex- 

 ture will then appear in situ, and in a state of integrity. By repeat- 

 ing these dissections w-ith slight alterations, every structure will be 

 demonstrated in a variety of ways." p. 35. 



Mr. Tod next proceeds to discuss tlie respective functions of the 

 different parts of the car, in the following order: 



Physiology of the Ear. — Of the Functions of the Auricle — 

 Meatus Externus — iVIembrana Tympani — Ossicula Auditus — 

 Chorda Tympani — Cavitas Tympani — Eustachian Tubes — Fenestra 

 Ovalis and Rotunda— Labyrinth. 



The author subsequently discusses the causes and the treatment 

 of the several malformations and diseases to which the structures of 

 this organ are liable. It has often been regretted that the members 

 of a profession which has conferred the greatest benefits upon man- 

 kind, should have so much excluded from their investigations the 

 pathology of congenital imperfections, and in particular of those 

 which affect the structures of the car, as to have caused the deaf 

 and dumb to be educated merely as incurables, instead of being put 

 also under a proper train of medical and surgical treatment. To so 

 great an extent, indeed, has the system of excluding congenital im- 

 perfections from pathological research been carried, that the bare at- 

 tempt of any individual to alleviate the symptoms arising from a 

 deformity has been sufficient to hold him up to the ridicule of his 

 brethren ; a circumstance which probably has deterred many from 

 devoting a j)ortion of their time to the investigation of these pha?- 

 nomena; and has also tended greatly to the encouragement of em- 

 piricism. In the work before us is shown the possibility that many 

 cases of congenital deafness and of auricular disease arc susceptible 

 of relief ; — it may thus prove the means of conferring important be- 

 nefits upon those who are, or may be, visited with maladies so dis- 

 tressing. 



The work concludes with remarks on several imperfections of the 

 organ of speech, which are of the same nature as those relating to 

 the cEconomy of the ear. 



As a scliool book, we are persuaded that Mr. Tod's Treatise on 

 the Ear must soon be in the hands of everj' medical student, of 

 whose library it will afterwards form a volume, as a manual oi' the 

 anatomy and physiology of that organ. 

 T/iird iicrics. Vol. J. No. 5. Nov. 1832. .'i C 



