2038 
tribution of nerve-fibres and ganglionic masses in the brain, 
which is very necessary, if not strictly histological. With re- 
spect to the structure of the grey or cortical substance of the 
brain, we note that Meynert recognises as the general type of 
cortical structure of the cerebral hemispheres, five layers— 
1, the external stratum of small scattered cortical corpuscles or 
nerve-cells (with predominating basis substance or connective- 
tissue); 2, stratum of closely-set small pyramidal cortical 
corpuscles ; 3, stratum of large pyramidal cortical corpuscles ; 
4, stratum of closely-set, small, irregular cortical corpuscles 
(granular layer); 5, stratum of spindle-shaped cortical cor- 
puscles. Besides this predominant type, there are other plans 
of structure which prevail in particular parts of the brain. 
Thus, he describes as the second type of structure that which 
is met with in the occipital convolutions, and especially in the 
sulcus of the hippocampus minor; in which the fourth or granu- 
lar layer predominates and beconies very complex, so that 
there are in all eight strata. (This part of the brain was taken 
by Lockhart Clarke as the starting point of his researches, but 
by a difference of arrangement he makes six instead of eight 
strata). A third type is represented by the structure of the 
convolutions of the sylvian fissure, where the spindle-shaped 
corpuscles are more especially developed, or the fifth stratum 
predominates. A fourth type is seen in the temporal portion 
of the gyrus fornicatus and in the subiculum cornu ammonis ; 
and is characterised by the great predominance of the pyra- 
midal cortical corpuscles or third stratum of the typical cortical 
structure and deficiency of the other strata. Finally, a fifth 
type of structure is displayed in the olfactory bulb, which, 
when compared (as it must be morphologically) to the cerebrum 
itself, shows, beside an external layer of structures connected 
with the olfactory nerves, a layer of pyramidal nerve-cells 
corresponding to the second and third strata of the cerebral 
cortex (the stratum gelatinosum of Lockhart Clarke), and 
within this a stratum of irregular cells corresponding to the 
fourth or granular layer of the cerebrum, or to the granular 
layers of the retina. The interesting and complicated details 
of the arrangement of nerve-fibres in the brain must be read 
in the original, which will, we hope, soon appear in English. 
A very full list of literary references is appended. 
Terminations of Nerves in the Tongue.—In the last part of 
‘ Stricker’s Histology ’ an excellent account is given by Engel- 
mann of the structures discovered by Lovén and Schwalbe in 
the tongue of mammalia, which appear to be the true organ 
of taste. The account of these organs in the rabbit, given 
by H. v. Wyss, formerly referred to in this Journal, agrees 
VOL. XI.—NEW SER. Oo 
