. A text-book of animal physiology [microform] : with introductory chapters on general biology and a full treatment of reproduction, for students of human and comparative (veterinary) medicine and of general biology. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. VISION. 601 enting a large onvex cornea, iris; eyelids may be made eye, and thus ns of the scle- is a peculiar d, of which it i like it very the falciform ) fish and the )arance it is 8, on account liary muscle, of accommo- it on account progression, e to alter the bove brief ac- ent gra
. A text-book of animal physiology [microform] : with introductory chapters on general biology and a full treatment of reproduction, for students of human and comparative (veterinary) medicine and of general biology. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. VISION. 601 enting a large onvex cornea, iris; eyelids may be made eye, and thus ns of the scle- is a peculiar d, of which it i like it very the falciform ) fish and the )arance it is 8, on account liary muscle, of accommo- it on account progression, e to alter the bove brief ac- ent grades of it its modifi- snces in the to have been vival of the adapted to its arts. , insects, etc., f extreme in- ard complete f darkness in ly within the 8 been found If atrophied. )ss of losing es; and some though well- ites are often V one bird of would gain id leave off- It is, of course, impossible to trace each step by which the vertebrate eye has been developed from more rudimentary forms, though the data for such an attempt have greatly accumulated within the last few years; and it is not to be for- gotten that even t1ie vertebrate eye has many imperfections, so that no doctrine of complete adaptation, according to the argument from design as usually understood, can apply. Certain acquired imperfections of the eye seem to be multi- plying at the present day, such as myopia, weakness of the accommodative mechanism, etc. The excessive use of the eyes, necessitating undue exercise of this apparatus or strain of the accommodation, is the fruitful source of evil. A good light— that is, one both sufficient in quantity and falling in the right direction upon the eyes and the objects to be viewed, together with adequate ventilation of the rooms occupied—is of great importance, though, as in the case of other organs, it is impos- sible to avoid wholly the penalties of over-use of the visual apparatus. It is of great importance to recognize that what we really see depends m
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Keywords: ., bookauthormillswes, bookcentury1800, bookdecade1880, bookyear1889
