The elements of embryology (1874) The elements of embryology elementsofembryo01fost Year: 1874 22 THE HENS EGG. [CHAP. It is not certain whether impregnation takes place previous to the deposition of the albumen, or whetber the spermatozoa bore their way through tbe albumen. The former would appear to be the more probable view, though the fact that Oellacher has found spermatozoa in the albumen, speaks in favour of their being involved in the depositing albumen, and so being brought in contact with tue blastoderm. According to Coste, Ilistoire du developpement des corps organizes, the access
The elements of embryology (1874) The elements of embryology elementsofembryo01fost Year: 1874 22 THE HENS EGG. [CHAP. It is not certain whether impregnation takes place previous to the deposition of the albumen, or whetber the spermatozoa bore their way through tbe albumen. The former would appear to be the more probable view, though the fact that Oellacher has found spermatozoa in the albumen, speaks in favour of their being involved in the depositing albumen, and so being brought in contact with tue blastoderm. According to Coste, Ilistoire du developpement des corps organizes, the access of the cock to the hen once in seven days is sufficient. We have no positive evidence that the spermatozoa make their way through the vitelline membrane and so gain access to the germinal, disc; but, as will be seen in a later part of this work, analogy renders such an event probable. 14. At about the time when the shell is being formed round the esfg, the germinal disc undergoes a remarkable change, known as segmentation. We shall have occasion to treat more fully of the nature of segmentation when we come to consider the amphibian ovum in which the various steps of the process may be more easily and satisfactorily traced. Meanwhile, inasmuch as the segmentation of the
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