micro cephalic icliot with bilateral porencephaly . 495 
the folia. The molecular and nuclear layers call for no special 
description. 
7. The splenium of the corpus callosum with the adjacent 
structures (Fig. 18). 
Fig. 18. Tracings through the splenium corporis callosi. The shaded area denotes 
the splenium in the microcephalic brain. The fainter line is from a tracing of 
a normal corpus callosum ( x 2). 
The splenium is absolutely much smaller than in the normal 
brain. The body of the splenium consists of transversely-directed 
fibres among which no patches of degeneration can be seen in 
Weigert preparations. But upon the upper aspect is a band of 
degenerated tissue with multitudes of oily-looking droplets. This 
zone contains a certain number of longitudinal fibres, no doubt 
belonging to the longitudinal striae. Again on the lower surface 
of the corpus callosum is another broad zone of degenerate tissue 
with characters similar to those observed in the upper zone just 
described. The fornix is thickened and (probably in consequence 
of the attenuation of the splenium) is not so closely applied to 
the corpus callosum as usual. 
8. The extreme end of the right occipital lobe. The sections 
are in the horizontal plane. 
Cortex and white matter can be distinguished. But important 
modifications are evident. The tangentially-directed stria of 
Gennari is not present, and this is of especial interest in view of 
the absence of the external geniculate body. The corresponding 
cortex of the left hemisphere contains a stria of Gennari visible 
macroscopically. The cortex of the cuneus immediately superior 
to the retro-calcarine sulcus is greatly deficient in nerve-cells, 
while it is absolutely crowded with the hyaline drops so often 
mentioned in the preceding notes. They seem particularly 
numerous beneath the pia mater upon the superior lip of the 
sulcus. 
