. Hand-book of physiology . vesti-bule, which terminate by again communicating with the samecavity. The Eustachian tube, the cavity of the tj-mpanum, and theexternal auditory passage, are remains of the first branchialcleft. The membrana tympani divides the cavity of this cleftinto an internal space, the tympanum, and the external mucous membrane of the mouth, which is prolonged inthe form of a diverticulum throuah the Eustachian tube intothe tympanum, and the external cutaneous system come intorelation Avith each other at this point, the two membranesbeing separated only by the pro
. Hand-book of physiology . vesti-bule, which terminate by again communicating with the samecavity. The Eustachian tube, the cavity of the tj-mpanum, and theexternal auditory passage, are remains of the first branchialcleft. The membrana tympani divides the cavity of this cleftinto an internal space, the tympanum, and the external mucous membrane of the mouth, which is prolonged inthe form of a diverticulum throuah the Eustachian tube intothe tympanum, and the external cutaneous system come intorelation Avith each other at this point, the two membranesbeing separated only by the proper membrane of the tym-panum. DEVELOPMENT OF THE ALIMENTARY CANAL. 701 Development of the Alimentary Canal. The alimentary canal, wliicli, as already described, is a kindof diverticulum from the umbilical vesicle, is at first an uni-form straight tube, which gradually becomes divided into itsspecial parts, stomach, small intestine, and large intestine (). The stomach originally has the same direction as F/^-. 101.*. * Fig. 101. An embryo dog, representing the junction of the umbiHcalvesicle with the intestinal canal, a, rudimentary nostrils; b, mdimentaryeyes; c, the first visceral arch; d, the second visceral arch; e,, the right,/, the left, auricular appendage; g, the right, h, the left, ventricle of the 702 DEVELOPMENT OF THE ALIMENTARY CANAL. the rest of the canal; its cardiac extremity being superior, itspylorus inferior. The first changes of position which the ali-mentary canal undergoes consist in the stomach assuming anoblique direction, and in the small intestine taking a newcourse from the stomach towards the navel, and, after makingan abrupt bend there, returning towards the middle of thebody in order to make its final curve to reach the anus. The Fig. 102. Fiy.
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectphysiology, bookyear1
