Our eyes, and how to take care of them / by Henry W. Williams.

  • Henry Willard Williams
Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: Our eyes, and how to take care of them / by Henry W. Williams. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

    12/114 page 8
    Even bone would have been a less perfect protection for the delicate internal parts than is the light tissue which forms the framework of the globe, — so yielding in its elasticity, yet so firm in its tough resistance. In front, we find the strong white membrane, the sclera, modified to a transparent structure, the cor- nea, an equal safeguard against intruding enemies, and giving unimpeded entrance to light alone. The nerves and blood-vessels, which, if placed in it, would have weakened the fibrous envelope, are included in another interior membrane, the choroid; and within these is spread out the delicate nervous perceptive tissue, the retina, to which all the other parts are auxiliary and subservient. Upon this images of all visible Nature are pictured: from it the fleeting impressions are tele- graphed to the brain, and we are conscious that we see. But, to this function of seeing, other condi- tions are essential. The eyeball, the most
    digitised image 1
    digitised image 2
    digitised image 3