The Nature of the Tectorial Membrane 115 



others were gently washed from the slide with and into the stain 

 chosen. After trying several stains, including haematoxylin and 

 methylene blue upon the fixed specimens, the Ijest results were obtained 

 with 0.1 per cent aqueous fuchsin, applied from 30 to 60 minutes. 

 While this stains the interfibrillar matrix of the membrane, it stains 

 the fibers more deeply, and it is both permanent and desirably trans- 

 parent. From the stain solution, the specimens were carefully rinsed in 

 water and mounted in glycerine or gtycerine jelly, usually with the 

 under surface upward. Some of the membranes removed entire were 

 broken in handling during the staining; others were broken by the 

 cover glass in mounting, hut at these stages the pieces could he oriented 

 with ease, and studies and measurements of them could be made witK 

 practical certainty as to locality. In all the author was able to obtain 

 nine tectorial membranes deemed sufficiently intact and oriented for 

 such measurements as are here given. 



The study of the teased specimens was supplemented by the use of 

 sections, some in celloidin and some in paraffin. Some cut vertical to the 

 apex of the cochlea, some tangential and some horizontal. Certain of 

 them were stained with the usual ha3matoxylin-Van Gieson stain; 

 others, for microchemical studies, after being appropriately fixed and 

 embedded, were stained, some with Meyer's muchsmatin, others with 

 Mallory's stain for white fibrous tissue. 



To study a point which arose concerning the development and later 

 attachment of the tectorial meml^rane, sections were made of the cochleae 

 of pigs varying gradually from 3 centimeters to 18 centimeters in 

 length. These were fixed, some in Zenker's and some in Gilson's fluid, 

 and all were stained l^y the lia^matoxylin-Tan Gieson method. 



The Physical Characters of the Tectorial Membran^e. 



The investigation of the mammalian cochlea may be said to have 

 begun in 1847 with the researches of Todd and Bowman, but Corti's 

 "Recherches sur I'organe de Void des mam mi fares'' appearing in 1851. 

 really formed the starting point of the long series of observations which 

 have appeared aliont equally distributed through the years since that 

 time. It was in this monograph that Corti not only descriljed for the 

 first time the organ which now l^ears his name, but also the structure 

 which spans the spiral sulcus and extends above his organ. This super- 

 structure was shortlv afterwards ag-ain described bv Claudius and 



