74 JouRNAL OF COMPARATIVE NEUROLOGY. 
The principal aim of the research is an elucidation of fibre-tracts 
rather than the investigation of nerve-cells. 
In a later research (’92), EDINGER applied essentially the 
same methods to the interbrain of selachians and amphibians, 
and the results have a scope similar to those just noticed for 
the forebrain. In the later editions of his text-book (1900), he 
has amplified for the comparative portion of the work the re- 
sults of all his own studies, together’ with those of others, giv- 
ing us the broadest exposition of modern comparative neurol- 
ogy yet attempted by any writer. 
To SAUERBECK (’96) belongs the credit of first publishing 
results from the application of chrome-silver impregnation to 
the selachian brain. The paper contains a very brief descrip- 
tion of those neurones and supporting elements which had been 
impregnated; by far the greater number of structures present 
evidently were not demonstrated at all. The treatment is quite 
unequal for the several regions, and the figures are drawn on a 
small scale. While SAvERBECK must not be given credit for the 
things he neither described nor portrayed, yet a first attempt 
in this field is certainly to be commended. 
ScHaPER (98), in the course of a series of studies on the 
cerebellum of vertebrates, has taken occasion to apply the 
chrome-silver method to the selachian cerebellum. His paper 
records observations with a considerable degree of detail. Ref- 
erence to the results of ScHAPER will be made more particularly 
under Section V. 
Inspired by the elaborate classification of nerve-cells in 
general promulgated by Nissi in his writings, SZCZAWINSKA 
(98) was impelled to make a study of the internal structure of 
the selachian nerve-cell. His work presents the results of his 
researches upon certain types of cells through the use of 
methylen-blue, safranin, and haematoxylin stains. The cells 
studied were from the sensory ganglia, motor cells from the 
cord and oblongata, and cells of PurKiNjE from the cerebellum. 
SzczZAWINSKA reached the conclusion that the nerve-cells of sela- 
chians have remained on a low plane of development. In sup- 
port of this view he cites certain of his results—(1) that the 
