334 Proceedings of Boyal Society of Edinburgh. [may 7, 
fond of children, otherwise passionate. Died of pleuro-pneumonia. 
Calvarium unsymmetrical and dense, shelving anteriorly. On sepa- 
rating the two hemispheres, the almost entire absence of the corpus 
callosum was apparent, and the velum interpositum exposed to 
view. A small cartilaginous-like band, inch broad and inch 
thick, situated opposite the corpora striata, was the only representa- 
tive of the great commissure. The fornix was represented by two 
thin posterior pillars ; the body of the fornix and its anterior pillars 
absent. Right optic thalamus much larger than left; posterior 
cornu of lateral ventricles was distended with straw-coloured serum ; 
pineal gland size of a wild cherry ; middle commissure absent. 
4. Cases where Absence of Corpus Callosum {or part of it) probably 
Secondary {to Hydrocephalus^ Hydatids^ or Tumours). 
XX Y. Gausser, Wiener Zeitschrift^ xi., 5th June 1845. — Epileptic, 
26 ; central part of anterior half of the corpus callosum, also septum 
lucidum and anterior and middle parts of fornix, absent. Dropsy 
of fifth ventricle. 
XXVI. Birch-Hirschfeld, Arch. f. HeiTkunde^ viii. p. 481. — 
Man, 41 ; of ordinary intelligence. Anterior half of corpus callosum 
absent ; dropsy of third ventricle (and evidently the fifth) separat- 
ing the two septa lucida ; a cavity containing fluid in the left frontal 
lobe communicating with the third ventricle. 
XXVII. Foerg, loc. cit.., pp. 17-25; see Sander, 7oc. cit, p. 136. — 
Middle part of corpus callosum and body of fornix absent ; other- 
wise everything normal. 
XXVIll. Solly, specimen in St Thomas’s Hospital Museum. — 
Boy, 16 ; died seven days after fracture of skull. Mother says “ he 
was never right from his birth,” and supposed that his weakness of 
intellect was due to a difficult labour. He had always difiiculty in 
controlling and regulating the action of his muscles so as to main- 
tain the erect position, and was always stumbling and rolling 
about; he generally appeared drowsy; he was fond of reading 
(religious books being his favourites), hut was unable to give a 
clear account of anything he had seen or read; childish in his 
amusements ; he sometimes talked naturally, hut was generally 
“ booby fied.” Corpus callosum completely absent. A pale mem- 
branous bag protruded from left side, which on being cut into was 
