FIB li U95 



Observations on the structure of the central fovea 

 of the human eye 



by 

 C. H. Golding Bird, F. E. C. S. and E. A. Schäfer, F. R. S. 



(With pi. I and 4 figs, in the text.) 



In his classical dissertation "On the Retina of Man and Verte- 

 brates " Heinrich Müller i) gives a minute account of the structure of 

 the macula lutea and of its contained central fovea. Long previous 

 to that time the view which held that the central fovea was a hole 

 in the retina had been given up and it had been described by Michaelis 

 as a fossa from Vio'" to Ys'" (0"2 mm. to 0'4 mm.) in depth, a mea- 

 surement which Müller acquiesces in. The latter further describes the 

 depression as measuring about 0-2 mm. in diameter in the vertical 

 meridian and as dipping in at first gradually afterwards more steeply. 

 He states that it appeared to him to have an elongated form (we 

 presume in the horizontal meridian). Although the various layers are 

 described by Müller as diminishing greatly in thickness at the fovea, 

 he states that only the inner molecular layer seems entirely to dis- 

 appear and that "certainly the inner granule layer does not con- 

 stantly fail in the middle of the fovea". Müller further makes the 

 pregnant remark "Es ist nur indessen mehr als wahrscheinlich, dass 

 in der Conformation der Grube und damit auch in der Anordnung der 

 Netzhautelemente daselbst nicht unerhebliche individuelle Verschieden- 

 heiten vorkommen, welche mit Entwickelungszuständen zusammenhängen 

 mögen". 



^) Anatomisch-physiologische Untersuchungen über die Retina des Menschen 

 und der Wirbeltiere. Zeitschrift für wissenschaftliche Zoologie. 1856. p. 1—122. 

 Internationale Monatsschrift für Anat. u. Phys. XII. 1 



