60 
MR. W. BEVAN LEWIS OR THE COMPARATIVE 
Relative Increase of Connective Matrix. 
Examination of the brain of animals below Man in the scale of organization shows 
in a striking manner that the comparative amount of connective to nerve elements is 
greatly increased. This fact I have already drawn attention to in discussing the rela¬ 
tive and absolute depth of the first layer of the cortex in different animals—a layer 
which in all cases essentially consists of a larger amount of connective than the sub¬ 
jacent strata.* Meynert also gives a table illustrative of this point, t Independent 
of the increase in relative and absolute depth of this layer, we have by these investi¬ 
gations been taught to recognise a great increase in the quantity of the cellular 
constituent of this matrix in the form of Deiter’s corpuscles, which crowd the upper 
regions of this layer. In Man they appear in scanty numbers ; in the Barbary Ape 
they become more frequent; in the Cat and Ocelot they are still more abundant; in 
the Pig and Sheep so profusely scattered are they that they form a most characteristic 
stratum immediately below the pia mater, and the meshwork formed by their fibres is 
dense and coarse, binding the blood-vessels to the cortex and rendering the pia mater 
strongly adherent (Plate 6). We find these corpuscles more freely in human brain 
which has undergone senile degeneration and in other diseases attended by reductions 
in functional activity and vascular affections resulting in retrogressive changes and a 
reversion to a low type of structure. 
The Globose Cell and its Affinities. 
It has been already mentioned, when referring to the nerve-cells of the second layer 
of the Pig, that peculiar globose elements occur here with few processes, and no angular 
projections as in the angular cells which enter into the constitution of the fourth layer. 
These cells, which are more numerous in some regions than others, are peculiar in that 
they resemble none of the usual elements described as forming the various layers of 
the cortex. They look like small pyramidal cells whose angles have been rounded off 
by the uniform swelling of the cell, and in most of these cells the apex process can 
alone be seen. It is interesting to note that these cells are found in the third and 
second layers of the cortex in the Ape, and that I have never recognised them in any 
human brain except in the brain of idiots and imbeciles, where they appear in 
abundance. 
The most characteristic feature presented in the cortex of idiots which I have had 
the opportunity of examining, has been the presence of these peculiar elements, which 
to a great extent take the place of the ordinary pyramidal cell of the second and third 
layer. Their essential characters consisting in their swollen, globose contour, and great 
paucity of branches. 
* ‘Brain,’ part 3, October, 1878. 
f “ Brain of Mammals,” by Th. Meynert, in Stricker’s ‘ Human and Comparative Histology,’ Syden¬ 
ham Society, vol. 2, p. 383. 
