178 
THOMPSON YATES LABORATORIES REPORT 
PREVIOUS LITERATURE 
The literature directly referring to the subject is comparatively scanty. The first account of 
the microscopic structure of the brain of the bird was given by Stieda,* in 1869, w^hose Paper on 
the subject contains some excellent figures vi^hich, though unstained, plainly indicate the position 
of the great tracts running from the cerebral hemispheres to the thalamus and mesencephalon. 
Stieda also describes and figures the large cells in the roof of the aqueduct, w^hich are now^ 
believed to be the mesencephalic nucleus of the trigeminus. 
In 1883 BuMMt published his Paper on 'Das Grosshirn der Vogel.' The first part of this 
communication is devoted to a consideration of the general morphology of the Avian brain. The 
second portion describes some features of the microscopical anatomy. His descriptions are strictly 
limited to the cerebral hemispheres. 
Using the older methods of staining, he described in detail the course and origin of that 
large bundle of white fibres seen on the mesial surface of the hemispheres, which he named 
'Markbilndel der strahligen Scheidewand.' 
All writers agree in the main with his description of this tract. He also pointed out the 
existence of the large tracts passing from the cerebral hemispheres to the thalamus and 
mesencephalon, and of the great associational system of fibres on the base of the brain, now called 
the tractus occipito-frontalis, and named by him the ' Basal-Markbtindel.' Bumm's valuable 
contribution outlined the main facts of the anatomy of the cerebral hemispheres. 
In 1 891 a series of papers by C. H. TurnerJ appeared on the morphology and histology 
of the Avian brain. That part of it which deals with the subject which we have especially 
studied, viz., the course of the various tracts, is less complete than the remainder of the paper 
which describes the cell-groups. Unfortunately, the methods and staining employed by the 
writer do not give results which can be compared with those obtained by means of the Weigert 
method. 
Edinger§ has included the structure of the bird's brain in his researches on Comparative 
Neurology, and has employed the methods now universally used in tracing the course of nerve 
tracts, viz., those of Weigert and Marchi. His researches on the allied brain of the reptile have 
also been particularly valuable to us, and we have adopted, where comparable, the nomenclature 
used by him in describing the nervous tracts in this class of animals. 
Bellonci II and PerliaH have contributed to our knowledge of the optic tracts, and quite 
recently, while this paper was in progress, communications have appeared by Friedlander,** 
WALLENBERG,tt and MtiNZER and Wiener. 
* Stieda, 'Zeits. fur Wissen. Zoologie,' vol. 19, 1869. 
I Bumm, 'Zeits. fiir Wissen. Zoologie,' vol. 38, 1883. 
J ' Journal of Comparative Neurology.' 
§ Edinger, ' Vorlesungen fiber den Bau der Nervbsen 
Centralorgane,' 5th edit., Leipzig, 1896. 
II Bellonci, 'Zeits. f. Wissen. Zoologie,' vol. 47, 1888. 
f[ Perlia, ' Graefe's Arch, fiir Ophthalm.,' Bd. 35, 1889. 
** Friedlander, ' Neurolog. Centralblatt,' April, 1898. 
ff Wallenberg, 'Neurolog. Centralblatt,' June, 1898. 
J J Miinzer and Wiener, ' Monats. f. Psych, und Neurol.,' 
Bd. 3 and 4, 1898. 
