. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. Fio. 879. Fio. S78.âSection through head of chick on third day, showing origin of eye (after Tec), a, epiblait undergoing thickening to form lent; o, optic veeicle: Vâ flrat cerebral veeivie; V,, poatorior cerebral veeicle. It will be olxerved that the retina ia already diithicUy Indicated. Fio. S7V.âl«ter itagea in development of eye (after Cardial), a, cpiblaat; c, develop-
. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. Fio. 879. Fio. S78.âSection through head of chick on third day, showing origin of eye (after Tec), a, epiblait undergoing thickening to form lent; o, optic veeicle: Vâ flrat cerebral veeivie; V,, poatorior cerebral veeicle. It will be olxerved that the retina ia already diithicUy Indicated. Fio. S7V.âl«ter itagea in development of eye (after Cardial), a, cpiblaat; c, develop- ing lene; o, optic veatele. SO that the cavity is almost obliterated; the anterior portion, becoming thickened, ultimately forma the retina proper, while the posterior is represented by the tesselated pigment layer of the choroid. As this retinal portion breaks away from the superficial epithelium, the latter forms an elliptical mass of cells, the future lens, the changes of which in the formation of the cells peculiar to Uie lens illustrate to how great lengths differentiation in structue is carried in the development of a single oi^gan. It will thus be seen that the most essential parts of the eye, the optic nerve, the retina, and the crystalline lens, are, according to a general law, the earliest marked out The cornea, the iris, the choroid, the vascular supply, the sclerotic, etc, are all sec- ondary in importance and in formation to these, and are derived from the mesoblast, while the essential structures are traceable, like the nervous system itself, to the epiblastic layer. Any act of perfect vision in a mammal may be shown to consist of the following: (1) The focusing of rays of light from S4 .â iast)emxiamaiiiiMiM>ammifmts»mmm. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Mills
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Keywords: ., bookauthormillswes, bookcentury1800, bookdecade1890, bookyear1890
