EFFECTS OF DOMESTICATION ON THE FUNDUS OCULI 



63 



gray. Resembles the Bald Eagle. Pecten 

 large and apparently reaches posterior part of 

 lens. Optic nerve entrance entirely obscured 

 and optic nerve fibres are persistent at tem- 

 poral margin of the disc. Retinal reflexes 

 very distinct. At the upper and temporal 

 edge of the disc the white border of papilla 

 shows quite distinctly. Pecten very black 

 and in no part translucent; lies in well defined 

 coil-like folds. No definite visual areas can 

 be differentiated from the general fundus. 

 Fundus 'granular' in places. The refrac- 

 tion slightly hyperopic. 



Beginning with his experience as a student 

 in the Thierartzneischule of the University of 

 Berlin in 1888, the writer has examined the 

 eyes of many barnyard fowls, to find in them a 

 great variation in the fundus appearances even 

 of the same species. The following few de- 

 scriptions from notebooks will suffice to illus- 

 trate this point: 



Bantam cock (Gallus domesticus). Fun- 

 dus examination; direct, with electric ophthal- 

 moscope. Both backgrounds the same. The 

 whole eyeground is of a uniform 'pepper and 

 salt' and granular variety — the 'pepper' 

 predominating. The macular region shows 

 quite plainly, the fovea being represented by a 

 single star-like deposit which looks exactly 

 like (and may be) a crystal of cholesterin. 

 The disc is a long oval, almost but not en- 

 tirely covered by the pecten at each side but 



quite clear at either end. The pecten changes 

 size and position under the examination but 

 not so quickly as in the Crow, for example. 



Large and mature 'speckled hen,' with a 

 light, brick-red iris. Kept in laboratory of 

 St. Luke's Hospital as a source of pure avian 

 blood. The observations on the bantam 

 rooster just detailed almost entirely coincide 

 with the findings in this bird, except that no 

 single stellate formation in the macular region 

 was noticed. Skiascopy and pupil reflexes 

 almost the same. There was no noticeable 

 astigmatism developed in either. 



A great variety of fundal pictures — nor- 

 mal and abnormal — are presented by our 

 Domestic Pigeons. The following are notes 

 on the fundi of the Homing or Homer Pigeon : 

 The background is readily seen in all these 

 domestic Pigeons. It bears a close resem- 

 blance to that of the common Hen, except 

 that the macular region is better defined in 

 the Pigeon. The sprinkling of fine, dark- 

 brown pigment over a reddish background, 

 interrupted here and there with colored points, 

 generally yellowish and glittering, giving 

 the whole a uniform appearance like fine 

 'mixed tweed' cloth seen from a distance of 

 a few feet, is very characteristic of this class 

 of fundi. The pecten is relatively small, 

 clubbed, spiral, black-brown and prevents 

 one from seeing more than a third of the 

 ovate disc. 



