Labyrinth and Semicircular Canals in the Human Ear. 249 



The researches to which I refer are contained in two memoirs 

 read to the French Academy of Sciences in the year 1828, and 

 inserted in the Memoires of that body published in 1830; the 

 first of which memoirs relates to the case of birds, the second to 

 that of mammalia. Of the first, a Report* was drawn up by the 

 illustrious Cuvier, to whom, with MM. Portal and Dumeril, the 

 memoir was referred, and in whose presence the various experi- 

 ments were repeated. 



It results from M. Flourens's experiments, that in birds and 

 in mammalia the nerves of the semicircular canals, whatever 

 other functions they may possess, unquestionably exercise this, 

 viz. of regulating the motions of the head, and of the animal 

 generally, of enabling it to preserve its equilibrium and to 

 move steadily in a given direction. No general description, 

 however, can give an adequate idea of the remarkable phenomena 

 developed in these memoirs. 



I shall therefore in the first place describe in considerable 

 detail the experiments and their results, which appear to have 

 attracted very little attention from writers on aural anatomy f. 



I shall next show how the effects described may be accounted 

 for — a branch of the subject upon which M. Flourens has not 

 entered. 



I shall finally consider the question whether the functions 

 thus shown to be possessed by the part of the animal economy 

 under consideration are or not exercised concurrently with others 

 of a totally different character — whether, in short, the semicir- 

 cular canals are to any, and what, extent operative in producing 

 perception of sound. 



I. The semicircular canals in birds, as in mammalia, are three 

 in number, two vertical and one horizonal, of which the largest 

 is vertical and superior. " The smallest is situated horizontally. 

 The canalis minor, or third of the series, is vertical. They con- 

 tain corresponding tubes of vascular membrane ; and they also 

 possess enlarged ampullae, on which the nerves are distributed 

 in the same manner as in mammalia." (Cyclopaedia of Anatomy 

 and Physiology, vol. i. p. 308.) 



The superior vertical canal is described as directed from be- 



* Ann. de Chim. et de Phys. 1828. To a reference to this Report con- 

 tained in the article on Sound in the Encyclopedia Metropolitana I am in- 

 debted for having my attention called to the subject of it. 



t I find no mention of them in the admirable and very complete resume 

 of the subject drawn up by Mr .Wharton Jones for the ' Cyclopaedia of Ana- 

 tomy and Physiology' eight years after the publication of Cuvier's Report; 

 and I do not find the omission repaired in any later treatise on the subject 

 which has come under my notice. Mr. Jones appears to have been ac- 

 quainted with some earlier speculations of M. Flourens. See ' Cyclopaedia/ 

 vol. ii. p. 5/0. 



