16 
in birds, not the same as those seen during life. This is especially 
true of the vascular pecten, projected forward in the posterior cham- 
ber ? and seen during life as a moving, ever-changing, black body. 
We see with the mirror the living nerve-liead, of all possible shapes 
and sizes, nearly always white or whitish, and generally covered with 
the pecten, although sufficiently free of it to recognize its outlines 
and sometimes most of its surface. The coloration of the fundus 
in birds does not present that marked variety that one observes in 
the other sub-kingdoms, especially among the mammals and rep¬ 
tiles. It is, however, never “black/ 7 as alleged by some authors, 
but is generally gray, with a suspicion of red—the red color being 
more plainly seen and variously distributed according to the family 
to which the bird belongs. Within bounds more limited than in the 
mammalian fundi opaque nerve fibers are generally seen, and the 
foveas can usually be distinguished. The macular region of the owls 
(following the rule that animals with binocular vision have this area 
ophthalmoscopically well marked) can be readily seen with the 
mirror, and it is generally observed as a well-defined reddish spot. 
(See Plate I.) During a fundus examination continual variations 
in the size, position and shape of the pecten will at first confuse the 
comparative ophthalmologist, but after a while he will make his 
exploration of the background and ignore these changes, just as he 
does some of the annoying corneal reflexes in man. 
The examination by the erect image will, on the whole, be 'found 
the most satisfactory method, although^ as in viewing the human 
fundus, it is advisable to use the indirect plan at the outset. The 
self-luminous ophthalmoscope is quite satisfactory for this purpose, 
and is the instrument preferred by my fellow-worker, Mr. Head. 
It does not require a totally dark room, and (of extreme importance 
sometimes), one is able to dispense with a separate source of light. 
The objections to its use are, as in picturing the fundus of man, the 
presence of the reflexes, macular, retinal and corneal, as well as the 
exaggeration of the number and whiteness of opaque nerve fibers in 
the background. Mr. Head believes, however, that it has enabled 
him to obtain fundus views through small pupils and to distinguish 
variations in some animal backgrounds that he failed to appreciate 
with the older instruments. It is, of course, not my purpose to dis¬ 
cuss the whole subject here, but I would remind any of my readers 
