842 MAN 



brain stem, lying almost in the lateral meridian, and is inllnenced hut little 

 by the lateral deviation w hieh is so delmitelx |)resent in the ehange oi |)osition 

 of the dorsal medullary nuelei. The nueleus ]:)resents a few lateral extensions 

 w hieh proeeed outward between the descending trigeminal libers particularly 

 in the region where the nucleus of Blumenau appears, and it is diHieult to 

 determine whether the latter belongs to the trigeminal complex or to the 

 nucleus of the coluniii of Burdach. At the lexel of the entrance of the cochlear 

 division of the eighth nerve, the substantia gelatinosa trigemini undergoes 

 a definite diminution in size, recedes Irom the surface of the stem, then gradu- 

 ally increasing in size it becomes flattened and applied to the lateral surface 

 of the reticular formation. As the nucleus continues upward it finally pre- 

 sents a dorsomesial inclination and disappears within the reticular forma- 

 tion, being covered on its lateral aspect by a prolongation of this nuclear 

 matrix which envelops it on its ventral, lateral and finally on its dorsal 

 as])ect. The disappearance of the substantia gelatinosa trigemini from the 

 surface of the reconstruction takes place abo\e the upj^er limit of the vesti- 

 bular nuclei. 



The Inferior Oli\akv Nlcleus 

 The inferior olivary nucleus appears in the lowest portion ol the recon- 

 struction as a narrow, llattenetl lamina of grax' matter disjjosed m an oblique 

 direction dorsomesially from the ventrolateral angU' of the reconstruction and 

 |)ointing toward the central gray matter. As this lamina, which is the \entral 

 accessory olivary luiekais, is followed upward there begin to appear masses of 

 gray matter in connection with it, dorsal to its mesial extremity. These repre- 

 sent the first appeaiaiui.' of the dorsal accessory oli\ar\ nucleus. As the 

 ventral accessory nucleus is tract'd birther it presents numerous irregularities 

 in size and shape and proceeds upward in a rc-lati\el\ constant position, con- 

 nected at its mesial extremit\ by a discontinuous series of nuclear bridges 

 with the dorsal accessorx nucleus, it comes to an vml at al)oiit the junction 



