1*'^ 

 ,' -. 



"MICROSCOPIC STUDIES ON THE CENTRAL 



NERVOUS SYSTEM OF REPTILES AND 



BATRACHIANS. 



By JOHN J. MASON, M.D., 



NEWPORT, R. I. 



ARTICLE III. 

 DIAMETERS OF THE NUCLEI OF THE LARGE NERVE CELLS IN I HK 



SPINAL CORD {continued^, also of those which give 



ORIGIN TO THE MOTOR FIBRES OF THE 

 CRANIAL NERVES. 



SINCE writing article II of this series, I have met with 

 nothing which could fairly be regarded as an objec- 

 tion to the law then presented, but have, on the contrary, 

 noted many new facts which tend to strengthen it and 

 widen its application. Nuclei which, by means of the pro- 

 longations of their surrounding cell masses, are related to 

 muscles, have been carefully measured throughout the 

 entire nervous system. 



Scattered cells, like those found singly or in pairs near 

 the course of the abducens nerve, with those which I have 

 elsewhere described as existing in the meshes of the raphe 

 of the alligator, and certain large cells in lizards, serpents, 

 and turtles which appear to be connected with the acoustic 

 or facial nerves, may all be classed as of doubtful function. 

 Although the diameters of their nuclei may in some cases 

 seem to furnish exceptions to the rule, so long as their 

 anatomical relations remain obscure nothing can be defi- 

 nitely affirmed about them in this connection. 



Reprinted from the Journal of Nervous and Mental Disease, Vol. viii 

 No. I, January, 1881. 



