1888.] Dr A. Bruce on Absence of Corpus Callosum. 331 
view of Onufrowicz). Gyrus fornicatus absent, or rolled inwards 
towards the association bundle, but separated from it by a deep 
fissure. Calloso-marginal sulcus {c.m.) abnormally far forward (?). 
Parieto-occipital {p.o.) and calcarine (c) fissures do not unite. A 
series of transverse sections are figured (see figs. 22, 23, 24, 25), 
showing the relation of the so-called frontal occipito association 
system to the fornix and gyrus fornicatus, and to the tapetum of the 
posterior cornu of the lateral ventricle. He quotes from Wernicke 
(Lehrbuch) to show that this system passes in the substance of the 
white fibres of the gyrus fornicatus along its whole length round the 
splenium of the corpus callosum into the gyrus uncinatus. Here, 
loG. cit.^ p. 231, he traces this bundle outwards over the lateral 
ventricle into the tapetum. How it gets back from there to the 
gyrus uncinatus is not very easy to understand. The cause of the 
lesion is supposed to be early hydrocephalus. 
XIV. Christie, Proceedings of Roy. Med. Chir. Soc., 1868, ref. 
m Lancet, 1868, p. 436. — Male, aged 20; idiotic, and without power 
of speech from birth. Brain weight, 28 J oz. ; corpus callosum com- 
pletely absent. 
XV. A. Virchow, Berlin, Gesellschaft f. Psychiatrie und N erven, 
9th May 1887, quoted by Kaufmann, loc. cit., p. 236. — Child died 
at 6 weeks with convulsions. Marked hydrocephalus ; no corpus 
callosum, no anterior commissure, no septum lucidum (no note of 
fornix). Many other developmental defects, and changes of 
inflammatory origin, such as thickening of pia, and adhesion to 
brain substance. 
2. Primary Partial Development of Corpus Callosum. 
XVI. Sander, loc. cit., p. 128 ; Arcliiv f. Psyhiatrie, vol. i. p. 
128. — Cretin, brain abnormally small, corpus callosum present, but 
splenium reduced to J centimetre, while genu is f centimetre in 
thickness ; psalterium of fornix present ; fornix, pes hippocampi, 
calcar avis, normal ; posterior of cornu of ventricle abnormally wide, 
forceps of corpus callosum quite absent. 
XVII. Sander,Voc. cit., p. 299. — Microcephalic boy, Smooths old. 
Corpus callosum present, but splenium too thin ; forceps present ; 
anterior commissure present, middle commissure absent ; fornix 
present, small ; septum lucidum normal, lateral ventricle not dilated. 
