DESCRIPTION OF PLATES. 



All figures were outlined with a Zeiss camera luciila at the level of the stage of the microscope, with the aid of 

 ocular No. 3 and 2 mm., homog. immersion. A pert. 1.30. 



PLATE 1. 

 FIG. 1. Radial vertical section of organ of Corti through the apical part of the cochlea. Dog 18 hours after 



birth. Fixation: osmic acid, trichloracetic acid. Stain: iron hematoxylin and Congo red. 

 FIG. 2. Section tangential to surface of organ of Corti through first turn and near apex of cochlea. Dog 12 hours 



after birth. Bouin's fluid, iron hematoxylin, and Congo red. 

 Fia. 3. Section tangential to surface of organ of Corti through first turn of cochlea. New-born dog. Trichloracetic 



acid, iron hematoxylin, Congo red. 

 FIG. 4. Section tangential to surface of organ of Corti through first turn of cochlea. New-born kitten. Osmic acid 



and Zenker's fluid; iron hematoxylin and Congo red. 

 FIG. 5. Section tangential to surface of organ of Corti through third turn of cochlea. Rabbit 10 hours after birth. 



Osmic vapors and Bouin's fluid; iron hematoxylin and Congo red. 

 FIG. 6. Section tangential to surface of organ of Corti through basal part of third turn of cochlea. Dog 3 days and 



10 hours after birth. Bouin's fluid, iron hematoxylin. and light green. 



PLATE 2. 

 FIG. 7. Section tangential to surface of organ of Corti through middle of third turn of cochlea. Dog 12 hours after 



birth. Bouin's fluid, iron hematoxylin, and light green. 

 FIG. 8. Section tangential to surface of organ of Corti through third turn of cochlea. Kitten 12 hours afterbirth. 



Trichloracetic acid, iron hematoxylin, and light green. 

 FIG. 9. Section tangential to surface of organ of Corti through second turn of cochlea. Kitten 3 days and 12 hours 



after birth. Osmic vapors and trichloracetic acid; iron hematoxylin and Congo red. 

 FIG. 10. Section tangential to surface of organ of Corti through first turn of cochlea. New-born dog. Trichloracetic 



acid, iron hematoxylin, and Congo red. 



FIG. 11. Section tangential to surface of organ of Corti through third turn of cochlea. Kitten 12 days after birth. 

 Osmic acid and trichloracetic acid ; iron hematoxylin and Congo red. 



PLATE 3. 

 FIG. 12. Section tangential to surface of the organ of Corti through first turn of cochlea. New-born kitten. Osmic 



acid and Zenker's fluid. Iron hematoxylin and Congo red. 

 FIG. 13. Section tangential to surface of organ of Corti through third turn of cochlea. Kitten 12 days after birth. 



Osmic acid and trichloracetic acid; iron hematoxylin and light green. 

 FIG. 14. Radial vertical section of organ of Corti through first turn of cochlea (before appearance of tunnel space). 



Dog 3 days and 18 hours after birth. Trichloracetic acid, iron hematoxylin, and Congo red. 

 FIG. 15. Radial vertical section of organ of Corti through third turn of cochlea (basal part). Kitten 3 days and 12 



hours after birth. Osmic vapors and trichloracetic acid; iron hematoxylin and Congo red. 

 FIG. 16. Radial vertical section of organ of Corti through second turn of cochlea. Dog 3 days and IS hours after 



birth. Trichloracetic acid, iron hematoxylin and Congo red. 

 FIG. 17. Section tangential to surface of organ of Corti through second turn of cochlea. Kitten 12 days after birth. 



Trichloracetic acid, iron hematoxylin, and Congo red. 



PLATE 4. 

 Fia. 18. Section tangential to surface of organ of Corti through apical part of second turn of cochlea. Kitten 16 hours 



after birth. Osmic acid and Bouin's fluid; iron hematoxylin and light green. 

 FIGS. 19 and 19'. Vertical spiral section of organ of Corti through second turn of cochlea. New-born kitten. Osmic 



acid and Zenker's fluid; iron hematoxylin and Congo red. 

 FIG. 20. Vertical spiral section of organ of Corti through third turn of cochlea. Rabbit 2 days after birth. Osmic 



acid and silver nitrate; iron hematoxylin and Congo red. 

 Fio. 21. Vertical spiral section of organ of Corti through second turn of cochlea. Doc 3 days and 18 hours after birth. 



Zenker's fluid, iron hematoxylin, and light green. 

 FIG. 22. Vertical spiral section of organ of Corti through second turn of cochlea. Dog 3 days and 10 hours after birth. 



Bouin's fluid, iron hematoxylin, and light green. 

 FIG. 23. Vertical spiral section of organ of Corti through second turn of cochlea. Kitten 12 days after birth. Osmic 



acid and trichloracetic acid; iron hematoxylin and light green. 



141 



