HISTORY AND METHODS OF INVESTIGATION. 11 



form. Among these may be mentioned the works of G-ottsche, Viault, Val- 

 entin, Micliicho-Malday, Baudelot, et al, who have given with exactness the 

 anatomy of the selachian and teleostean brain. The brain of the am- 

 phibian and of the reptile has been much studied by comparative anatomists; 

 there is, however, little of the older literature useful to the general mor- 

 phologist except the works of Treviranus and of Carus. 



But here was introduced the new technique of serial sections. Eeissner 

 and, later, Stieda were first to attempt to find their way through the difficult 

 field by the aid of sections, and to the last-named author we are especially 

 indebted for pioneer studies on the inner structure of the brain of the lower 

 vertebrates. After Stieda had sectioned and figured the brains of repre- 

 sentative fishes, amphibians, and birds, there rapidly followed other studies 

 in the same field. Kearly all classes of animals were investigated. Fritsch 

 devoted a beautiful monograph to the study of fishes. His statements, how- 

 ever, were later extended and in part much modified through a work by May- 

 ser: a work which should be counted among the classics of brain-literature. 

 Along with Mayser's monograph stands a work which may be especially 

 recommended: "The Description of the Brain of Petromyzon," by Ahlborn. 

 These works have laid the foundation for our present knowledge of the 

 brain of the lowest vertebrates. Still, for want of good technique, they have 

 been able to give but little relative to the minu.te structure. 



Tile investigations of the Italian, Giuseppo Bellonci, alone showed 

 what problems still resisted solution. Although Bellonci died young, the 

 few short papers which he left belong to the very best that we possess in 

 this field. Our knowledge of the brain of the lower vertebrates was given 

 an especial impetus through the embryologieal and comparative anatomical 

 studies of Eiickhardt, to whom, next to Stieda, we owe the possibility of 

 tracing the homology of single brain-structures of the lower vertebrates with 

 the corresponding parts of the much better known mammalian brain. In 

 America, where Mason had already published a comparative anatomical 

 chart, we may mention Spitzka and his pupils; then Osborn, to whom we 

 are indebted for important studies in commissures and on the amphibian 

 brain; and Herriek, who with great industry studied representatives of 

 every lower class. In England appeared the studies of Saunders. In Ger- 

 many "Wiedersheim, Ivoppen, Meyer, the author, and others were actively 

 at work. Prom Australia we have received from Elliot Smith excellent 

 studies on the brain of lower mammals. But for the most part the methods 

 were yet quite insufficient; so that, despite much work, little reliable ma- 

 terial was collected. The Amphibia and Eeptilia have been, comparatively 

 speaking, best worked, although certain parts of the fish-brain are at least 

 fairly well known. The knowledge of the avian brain is most fragmentary. 

 Its cerebral hemispheres have been studied quite insufficiently, though. 



