TRANSACTIONS OF THE SECTIONS. 155 
7. The membrana rotunda receives the pressure of the atmosphere 
through the eustachian tube, so as to enable the slopes to be raised. 
8. The water of the labyrinth received the full momentum of the 
impulses of the air on the membrana tympani without loss from con- 
densation, because the difference of the areas of the membrana tympani 
and fenestree ovales, combined with the difference of range of motion of 
the point of the malleus and base of the slopes, is egual to the difference 
of specific gravity between air and water. 
9. The perilymph oscillates between the two fenestre, and its alter- 
nate fluxes and refluxes over the membranous labyrinth excite the 
sensation of hearing. 
10. The cochlea regulates the extent of the oscillations of the peri- 
lymph by the expansion of its spiral lamine. 
11. The aqueducts of Cotugno are diverticula, by whick the peri- 
lymph is removed to the cavity of the cranium during the expansions 
of the spiral laminz. 
12. The petrous bone deafens the internal ear, so as to prevent any 
vibrations from acting on the perilymph, except those which have been 
previously adjusted for creating accurate oscillations by being’ trans- 
mitted by the ossicula. 
On the Connection between the Nervous System and Muscular Con- 
tractility. By Dr. Joun Ret. 
This communication was an extension of that made by Dr. Reid to 
the Association at Edinburgh. In the former communication facts 
were adduced to show, that when the contractility of a muscular bun- 
dle is exhausted in the cold-blooded animals by the application of gal- 
vanism, this property of contractility will again return, though all com- 
munication between the central organs of the nervous system and the 
muscles experimented upon had been cut off, by the complete division 
of the nerves passing between them. In the present communication it 
was stated that the same fact had been verified upon the warm-blooded 
animals. The same experiment has also been four times successfully 
repeated after section of the nerve upon the posterior extremities of 
the same frog. Dr. Reid then made some observations for the purpose 
of showing that the experiments made by Miller, and adduced by him 
in opposition to the Hallerian doctrine of contractility, are liable to a 
known source of fallacy. The disappearance of the contractility wit- 
nessed by Miller in the muscles supplied by the sciatic nerve in a rab- 
bit five weeks after that nerve was divided, was in all probability de- 
pendent upon the impérfect nutrition consequent upon inaction. Dr. 
Reid stated, that he found the muscles of the limb of a frog retain their 
contractility and their usual size two months after the section of their 
nerves, when they were daily exercised by sending slight shocks of 
galvanism through them. 
On Foreign Bodies in the @sophagus. By Mr. Gzorcz Guover. 
