Scanning Electron Microscopy of Shell-Membrane Formation in Hen's Eggs

鶏卵の卵殼膜の形成機構が,主として走査電顕によって,一部は銀染色によって形態的に観察された.

卵殼膜の形成は,卵管の峡部起始部において,先ず細線維とこの間隙を埋めるムチン様基質の構成によって始まった.この線維網が内卵殼膜の内層となった.峡部中央部で,内層の上にやや太い線維が加わって,内卵殼膜の外層が形成された.峡部末端部で,更に太い線維が加わって,外卵殼膜が形成された.

卵殼膜は,卵管峡部で形成を終わった。卵管子宮部では,既に完成した卵殼膜の上に,卵殼形成が進行した.
完成した卵の卵殼膜は,内側から外側に向かって,内卵殼膜内層,内卵殼膜外層,外卵殼膜の3層に大別された.

A morphological study on the shell-membrane of the chicken egg was performed in the course of developement by the use of a scanning electron microscope and the silver impregnation method.

The shell membrane began to form at the beginning of the isthmus by the formation of a coarse meshwork of fine fibers. Fine fibers were cemented with one another by mucin-like material to form a meshwork which became the inner layer of the inner shell membrane. Then relatively large fibers were added to the already formed meshwork of fibers of the inner layer in the middle portion of the isthmus. They developed into the outer layer of the inner shell membrane. Very large fibers were added to the inner shell membrane in the end portion of the isthmus. They developed into the outer shell membrane. The formation of the shell membrane was accomplished just before eggs descended to the uterus.

The shell membrane of the fully formed egg was divided into three layers, the inner and the outer layer of the inner shell membrane and the single layer of the outer shell membrane. The inner layer of the inner shell membrane is a thin layer adjoining directly to albumen. It is a mucin-like layer containing fine fibers. The outer layer of the inner shell membrane is formed by a meshwork of fibers about 2µ in diameter. These fibers are characterized by the presence of granular concretions around each fiber. The outer shell membrane is formed by a coarse meshwork of fibers 3-4µ in width. These fibers are combined with one another in such manner as to form knots.