;. during the Year 1828. ' i^M9 



lines thick ; but, under certain circumstances, and in certain 

 places, it is the thickness of an inch, which appears to M. Ma- 

 gendie to be a strong objection against a system which esta- 

 blishes a close affinity between the form of the skull and the 

 brain. 



M. Flourens, who made important experiments on the effect 

 produced by taking away different parts of the encephalon, has 

 this year applied his observations to the medulla spinalis and 

 medulla oblongata, with a view of ascertaining their exact 

 limits, and comparing their action upon the respiration of the 

 four classes of vertebrated animals. The results of these ex- 

 periments are, that the medulla spinalis may be abstracted with 

 less injury from Mammalia than from birds ; still more maybe 

 taken from certain reptiles, and fishes may be entirely de- 

 prived of it. This proves, says M. Flourens, that the medulla 

 oblongata is the essential and primordial organ of all mechani- 

 cal respiration, and the exclusive organ in fishes. The same 

 author has renewed his experiments on the canals of the ear, 

 which produced such extraordinary movements in the animals 

 on whom they were performed, and who, in spite of the dis- 

 order thus produced, continued in perfect health. The section 

 of a horizontal canal constantly keeps the head in motion 

 from right to left, and left to right ; and, when two canals are 

 cut, this movement becomes so rapid and impetuous, that the 

 animal loses its equilibrium, and turns round and round, with- 

 out the power of stopping. If, on the other hand, the exter- 

 nal semicircular canals be divided, the movement is up and 

 down, and frequently with such violence as to throw the ani- 

 mal back, head over heels. If the internal canals be cut, the 

 same movements take place, except that the animal is thrown 

 forwards, heels over head. These movements cease when the 

 animal remains perfectly still ; but, if it tries to move from one 

 place to another, they immediately recommence, and render 

 both walking and flying impossible. M. Flourens and M. Ma- 

 gendie have also tried experiments upon uniting nerves which 

 have been separated ; they have even brought the ends of dif- 

 ferent nerves together, which have completely united, and, in 

 some cases, even the functions have been entirely restored. 



M. Giroux de Buzaraingue has invented a peculiar method 

 of determining the functions of the encephalon. It is from the 

 inspection of the changes occasioned in sheep, by the malady 

 known under the name of " tournis," and finding the place in 

 the brain occupied by the parasitical animal which caused the 

 disease. Assisted by the curious researches of M. Magendie 

 on the cerebellum, as connected with the movements of ani- 



