Bibliographical Notices. 271 
oblongata, cerebellum, optic lobes, and cerebral and olfactory lobes 
of the brain, making important discoveries in every direction. The 
subject is treated in a comparative manner, so that each region is 
studied through a number of animals and under different powers of 
the microscope, the results being represented in 113 quarto plates, 
which have been selected, as the author states, from over 5000 
preparations, and form a comparative anatomy of the nervous sys- 
tem. The text, exclusive of the literature and explanation of the 
plates, only extends to twenty-four pages ; but this brevity is due 
to the setting down of nothing but results. The author first 
describes his method of hardening, and details some examples of the 
variation in hardening and staining which the species exhibit. The 
tailed Batrachians stain easily, but require a third more time to 
harden than specimens of other orders. The sections were stained 
after being cut, transparency produced by oil of cloves, and the 
slices were mounted under thin glass in Canada balsam dissolved in 
chloroform. These sections are photographed on glass and deve- 
loped with sulphate of iron, the glass having previously been coated 
with a solution of wax and benzole. The collodion-film is made 
adherent to a thin sheet of gelatine and removed from the plate, 
when it becomes available for the artotype process of printing, by 
which the beautiful results here presented were obtained. 
The spinal cord is exemplified in no fewer than forty-four plates, 
and elucidated in seven pages of text. As among higher animals, 
this organ consists of white and grey matter, and the white matter 
shows the usual division into six columns; but the cord is charac- 
terized by an absence of the superior or posterior fissure, so that the 
union of the posterior columns is closer thanin man. ‘Two longitu- 
dinal bundles of white nerve-fibres extend along the spinal cord in 
Saurians, between the inferior white and grey commissures, extend- 
ing forward from the lumbar region to form the central longitudinal 
bundle of the medulla oblongata on each side. These columns are 
especially conspicuous in the alligator, iguana, heloderma, skink, 
and anolis. The author finds that reptiles which are shielded by 
bony plates or by thick scales have the fibres of the superior 
columns of the spinal cord relatively smaller than in naked reptiles. 
The infero-lateral columns of the spinal cord are larger in the cer- 
vical than in the lumbar region. Some of the plates show well the 
“lateral ligament” of Dr. Mason. Other plates show the nerve- 
cells and the root-filaments of the nerves, together with their modes 
of exit. The contour of the grey substance in section is not unlike 
its contour in man, though in Ophidians the superior horns blend, 
and among Batrachians a reticular substance becomes interposed 
between the two halves of the grey matter. This substantia reticu- 
laris is equally large in the brachial and crural regions, and in the 
latter surrounds the central canal. This canal is lined with conical 
ciliated epithelium, and the processes given out from the cells in the 
frog’s spinal cord are shown to be continuous with the network of 
the substantia reticularis. This substance is admirably exhibited in 
the plates, and, according to the author, affords “ probably the best 
