[ 35 ] 
III. Researches on the Comparative Structure of the Cortex Cerebri. 
By W. Bevan Lewis, L.R.C.P. (Bond.), Senior Assistant Medical Officer, 
West Riding Lunatic Asylum, Wakefield. 
Communicated by Dr. Ferrier, F.R.S., Professor of Forensic Medicine, King's 
College , London. 
Received June 18,—Read June 19, 1879. 
[Plates 6, 7.] 
The object and scope of this paper are to detail the results of a full investigation into 
the minute structure of the cerebral cortex in the Pig’, and to add such notes upon the 
histology of the same structure in the Sheep and Cat as will suffice for a fair compara¬ 
tive view of those divergencies in fundamental structure which present themselves 
between the brain of these animals and that of the hio’hest members of the Mammalian 
series. Attention has been especially directed to the greater mass formed by the 
parietal, frontal, and upper arc of the limbic lobe," the inferior arc of the limbic lobe 
(gyrus hippocampi) and the olfactory lobe being left for subsequent examination. The 
method adopted has been that of slicing the hemispheres of fresh brain from end to end 
upon the freezing microtome, and examining each individual section, both in the fresh 
state and after preservation, by a method already described.! Tables containing 
details of the dimensions of cells and depth of layers accompany the paper, being- 
collated at the end for convenience of reference. 
The Convolutions of the Brain in the Pig. 
The regional distribution of ganglionic cells in the cortex of this animal constitutes 
so important a portion of our inquiry that, in order to avoid any obscurity in the sub¬ 
sequent sketch, it will be advisable to review briefly the arrangement of the convolu¬ 
tions and sulci. In doing so I shall follow the tenninology adopted by Professor 
Broca, in his late important work on the comparative anatomy of the convolutions 
in Mammals.J 
* The limbic lobe consists of the convolution of the corpus callosum, together with the gyrus hippo¬ 
campi (Broca). 
t “ Application of Freezing Methods to the Microscopic Examination of the Brain.” ‘ Brain,’ part 3, 
October, 1878. 
+ “ Anatomie Comparee des Circonvolutions,” par M. Paul Broca. ‘Revue d’Anthropologie.’ 
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