Royal Society. 323 



consequently traversed portions of the sun's atmospliere of very dif- 

 ferent thickness ; and that accurate observations of this kind would 

 put the hypothesis in question to a satisfactory test. The result of the 

 experiment was that no such differences could be perceived ; thus 

 proving, as the author conceives, that the sun's atmosphere is in no 

 way concerned with the production of the singular phsenomenon of 

 the existence of dark lines in the solar spectrum. 



A paper was also read, entitled " On the connexion of the anterior 

 columns of the Spinal Cord with the Cerebellum ; illustrated by pre- 

 parations of these parts in the Human subject, the Horse, and the 

 Sheep." Bv Samuel Solly, Esq., Lecturer on Anatomy and Physi- 

 ology at St. Thomas's Hospital, M.R.I., Fellow of the Royal Medical 

 and Chirurgical Society, and Member of the Hunterian Society. 

 Communicated by F. M. Roget, M.D., Sec. R.S. 



The exact line of demarcation between the tracts of nervous matter, 

 .subservient to motion and to sensation, which compose the spinal cord, 

 has not yet been clearly determined. The proofs which exist of a 

 power residing in the cerebellum which regulates and controls the 

 actions of muscles, would lead us to suppose that the fibres of the 

 motor nerves are continuous with those of the cerebellum ; but hi- 

 therto no observations have been made which prove the existence of 

 this connexion ; and it is the object of the author, in this paper, to 

 establish, by a more careful examination of the anatomical structure 

 of this part of the nervous system, such continuity of fibres between 

 the anterior columns of the spinal cord and the cerebellum. The 

 corpora pyramidalia have been hitherto considered as formed by the 

 entire ma.ss of the anterior, or motor columns of the spinal cord ; but 

 the author shows that not more than one half of the anterior columns 

 enters into the composition of these bodies : and that another portion, 

 which he terms the ayitero-lateral column, when traced on each side 

 in its progress upwards, is found to cross the cord below the corpora 

 olivaria, forming, after mutual decussation, the surface of the corpora 

 restiformia ; and ultimately being continuous witli the cerebellum. 

 These fibres are particularly distinct in the medulla oblongata of the 

 sheep and of the horse. The author conceives that the office of the 

 antero-lateral columns is to minister to the involuntary, as well as to 

 the voluntary movements : that the facial nerve arises from both the 

 voluntary and involuntary tracts ; and that the pneumogastric nerve 

 arises both from the involuntary and the sensory tracts, 



June 9. — " Discussion of the Magnetical Observations made by 

 Captain Back, R.N., during his late Arctic Expedition. By Samuel 

 Hunter Christie, Es(|., M.A., F.R.S. 



The author, having been consulted by Captain Back, previous to 

 the departure of the latter, in 1833, with the expedition for the relief 

 of Captain Ross, respecting the nature of the magnetical observa- 

 tions which it might be desirable to make in the regions he was about 

 to visit, and considering that, with a view to the attainment of the 

 principal object of the expedition, the greatest economy of time in 

 making these observations was of the first importance, limited his 

 suggestions, in the first instance, to the methods proper so be em- 



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