The Journal of 



Comparative Neurology and Psychology 



Volume XVI MAY, 1906 Number 3 



THE MIXED CEREBRAL NERVES IN MAMMALS. 



FREDERIC T. LEWIS, A.M., M.D. 



{From the Embryological Laboratory, Har^uard Medical School.) 



With Plate XVII. 



The occasion for this note is the difficulty of presenting the 

 embryology of the cerebral nerves to medical students in such a 

 way that it shall not be an added burden, but shall facilitate the 

 learning of human adult conditions. This difficulty may be 

 partially met by the adoption of a consistent nomenclature free 

 from synonyms, and by the use of such diagrams as are to be con- 

 sidered presently. 



The "Nomina anatomica" (N. A.) adopted by the German 

 society of anatomists should be the basis for future anatomical 

 terms.^ Its great advantages are the elimination of synonyms 

 and the substitution of descriptive for personal names. Since the 

 numbers applied to the cerebral nerves are synonymous with the 

 descriptive names, and lead to the erroneous idea that there are 

 twelve pairs of comparable nerves connected with the brain, it is 

 preferable to employ the names rather than the numbers. Four 

 of the cerebral nerves are mixed, consisting of a dorsal (sensory) 

 root and a lateral (motor) root. Naming these for their dorsal 

 portions they are the trigeminus, the intermedins, the glosso- 

 pharyngeus, and the vagus. Their lateral portions may be called 

 respectively the portio minor trigemini, portio facialis intermedii, 

 portio motoria glossopharyngei, and portio accessoria vagi. 



'Die anatomische nomenciatur. Arch. f. Anat. u. Entzu., Supplement-Band, 1895. This nomen- 

 clature is accessible to students in Barker's Laboratory Manual oi .\mitomy, J. B. Li ppincott Co., 1904. 



