. Artificial incubation and incubators ... da^ the ^olk iscompletely en- ^^^^^»^^^^» closed by the blas-toderm. The em ^^^^^mJU^^^ bryo appears in acurved shape; the ^^^^mJ/Ji^^^S:/ feet making theirappearance, look- ^^^^®M- IKWuW ing like faintstreaks on the end ^^^ftlfe^^^^^ °f tlie le£~like aP~pendages. By the ^4^1^^ end of the sixth day, the heart, FlG- 6- which was at first a simple tube, attains almost its complete form, and its covering—the pericardium—is first seen. On the seventh day the crop and rudimentary intestines maketheir appearance, the beak begins to develop, and if the shell
. Artificial incubation and incubators ... da^ the ^olk iscompletely en- ^^^^^»^^^^» closed by the blas-toderm. The em ^^^^^mJU^^^ bryo appears in acurved shape; the ^^^^mJ/Ji^^^S:/ feet making theirappearance, look- ^^^^®M- IKWuW ing like faintstreaks on the end ^^^ftlfe^^^^^ °f tlie le£~like aP~pendages. By the ^4^1^^ end of the sixth day, the heart, FlG- 6- which was at first a simple tube, attains almost its complete form, and its covering—the pericardium—is first seen. On the seventh day the crop and rudimentary intestines maketheir appearance, the beak begins to develop, and if the shell isbroken, the first movement of the limbs is seen. A rockingor pulsating movement of the whole embryo may be seen through the shell, if held beforenow becomes more fluidsorption of the white,day the embryo growsbeginning to form andthem. The embryo, attaken from the shell,. a strong light. The yolkowing to the rapid ab-From this to the tenthvery rapidly; the bonesflesh appearing onthe eleventh day, ifappears as shown atteenth day the toe-nailsformation of the scales Fig. 7. On the thir-appear and also the *IG- on the toes; the feather-sacs have sufficiently developed to showthe color of the coming chick. The fifteenth day a change ofposition takes place, the chick lying lengthwise in the shell; pre-vious to this, the embryo has lain as formed—crosswise; the billopens and closes, and distinct motions of the wings and legs maybe seen. By the close of the sixteenth day the white of the egg hasentirely disappeared. The yolk-sack connected to the chick by theumbilical cord lies loose between the body of the chick and the FINAL DEVELOPMENT. 23 shell-membrane, until the nineteenth or twentieth day, when it isdrawn into the abdomen of the chick. Fig. 8 shows the appearance of the chick on the nineteenth daywith the yolk-sack not fully absorbed. And Fig. 9, the
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectincubat, bookyear1883
