UNILATERAL CEREBELLAR AGENESIA 365 
the case reported by Edinger (Berliner Klinische Wochenscrift, 
Jahrgang 35, Nos. 4 and 5, 1898) which bears a remarkable 
resemblance to this. In Edinger’s case, a man of 46, it was the 
right half of the cerebellum which was defective. 
Sections through the cervical cord (fig. 6) do not reveal any 
very noticeable asymmetry. The right posterior horn is larger 
than the left but this is possibly due to the same causes which 
produced a narrower and longer clava and cuneus on the left 
(see p. 363). The left dorsal spino-cerebellar tract is, however, 
smaller than the right, being about 75 to 80 per cent of the size 
of the latter. 
Sections through the bulb at the caudal extremity of the 
inferior olivary nucleus (fig. 7) show the following asymmetries. 
The right nucleus cuneatus and nucleus gracilis are larger than 
the left; the right external nucleus of the column of Burdach 
is present but not the left; external arcuate fibers are present 
on the right lateral periphery but not on the left; the left nucleus 
arcuatus and left medial accessory and principal inferior olivary 
nuclei are larger than the right. Of these asymmetries the 
asymmetry of the nuclei of the columns of Goll and Burdach 
is due to their longer and narrower shape on the left and may not 
indicate any true inequality in their development. The leit 
external nucleus of the column of Burdach appears in sections 
further cephalad (fig. 8) and while it may be smaller in actual 
size than the right one this cannot be easily determined. Ex- 
ternal lateral arcuate fibers on the left appear in sections further 
cephalad and any true inequality is not very marked. Ventral 
external arcuate fibers are present here on both sides. It is not 
easy to ascertain slight inequalities in these on the two sides; 
but while those coursing around the pyramids are about equal at 
this level, further cephalad both those coursing around the pyra- 
mids and those running along the ventro-lateral periphery, 
outside the olive appear to be more numerous on the right. The 
left arcuate nucleus appears to be consistently larger than the 
right in sections through the lower olivary region but higher 
this nucleus disappears on the left and one appears on the right, 
but on the mesial aspect of the pyramid. If this latter be re- 
