320 Proceedings of Royal Society of Edinhiirgh. [may 7, 
ployed at a fixed temperature, whilst great care had to he taken 
that none of the material acted upon passed through the filters. 
The calcium salts were then estimated as before, and the difference 
between this and the amount originally present was calculated as 
the carbonate of lime dissolved. 
3. On a Case of Absence of the Corpus Callosum in 
the Human Brain. By Dr Alexander Bruce. (Plates 
YI.-XIII.) 
Cases of absence or defect of the corpus callosum are of interest 
not only because of their great rarity, hut because of the light which 
they throw on the distribution and functions of this commissure, 
and on the development of the mesial aspects of the cerebral hemi- 
spheres. 
The case here recorded came under my notice accidentally while 
examining the brain of a man who had died of pneumonia in the 
Edinburgh Koyal Infirmary in October 1886. During the short 
period of his stay in hospital. Dr Sillars, the resident physician, 
noted nothing peculiar in his manner or mental condition. His 
sister, whom I saw after his death, gave me the following account of 
him : — As a hoy at school he was generally backward. He could 
read, was good at mental arithmetic, hut never learned to write 
much more than to be able to sign his name. He was always some- 
what “dour” (obstinate) and eccentric, but in no way vicious or 
revengeful. He was fond of music ; always took an interest in what 
was going on around him. He was for thirteen years in the employ- 
ment of one firm, where he earned a pound a week as light porter. 
On applying to the manager of this firm, I learned that he was con- 
sidered “ queer,” though no one could say in exactly what way, hut 
that he discharged his duties satisfactorily. Some time before his 
fatal illness he became careless and untidy in his habits, and 
indulged very freely in alcohol. 
On removing the brain my attention was first directed to the 
absence of the corpus callosum. On separating the hemispheres, the 
frontal lobes of which were loosely united by the leptomeninges, it 
was seen that this commissure was completely absent, as was also 
