Principles and practice of operative dentistry . Fig. 92.—Longitudinal section of lip of kitten. X 30. ORIGIN, DEVELOPMENT, AND MORPHOLOGY OF THE TEETH. 27 ^—VSr^Z. Division of mammal ovum (half diagrammatic).1, the yolk divided into two globules (cells) withnuclei; 2, quadrupled ; S, a large number of nucle-ated cells ; 4, a, b, isolated cells. established,—and this is best studied in the egg of the barn fowl,—thereoccurs a rapid proliferation of embryonic cells in the germinal spot ordisk of Pander. This disk is atfirst composed of a germinal cell,which by the process of karyokine-sis—indire
Principles and practice of operative dentistry . Fig. 92.—Longitudinal section of lip of kitten. X 30. ORIGIN, DEVELOPMENT, AND MORPHOLOGY OF THE TEETH. 27 ^—VSr^Z. Division of mammal ovum (half diagrammatic).1, the yolk divided into two globules (cells) withnuclei; 2, quadrupled ; S, a large number of nucle-ated cells ; 4, a, b, isolated cells. established,—and this is best studied in the egg of the barn fowl,—thereoccurs a rapid proliferation of embryonic cells in the germinal spot ordisk of Pander. This disk is atfirst composed of a germinal cell,which by the process of karyokine-sis—indirect division or segmenta-tion of the cell—produces a rapidmultiplication of these elementalcells (Fig. 85, 1, 2, 3, 4). These embryonic cells soon ar-range themselves into two layers,known as the epiderm or epiblast,and the hypodenn or hypoblast, theepiblast forming the upper layerand the hypoblast the lower (). Later a third stratum of cellsis developed between the epiblastand the hypoblast, which is knownas the mesoderm or mesoblast ( and 88). From these three layers all ofthe tissues and the various organs of the body are developed. Fr
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectdentist, bookyear1901
