. The physiology of reproduction. Reproduction. LACTATION 559 the manner in which the substances of which the milk is formed pass out from the secretory cells. According to one view, the cells themselves break loose and become disintegrated, setting free their contents in the alveoli of the gland, just as in the case of the sebaceous glands. Another theory states that the cells simply excrete the substances into the alveolar lumina without becoming detached or destroyed themselves, as with the submaxillary mucous gland. According to the third hypothesis the mammary gland in its mode of activit
. The physiology of reproduction. Reproduction. LACTATION 559 the manner in which the substances of which the milk is formed pass out from the secretory cells. According to one view, the cells themselves break loose and become disintegrated, setting free their contents in the alveoli of the gland, just as in the case of the sebaceous glands. Another theory states that the cells simply excrete the substances into the alveolar lumina without becoming detached or destroyed themselves, as with the submaxillary mucous gland. According to the third hypothesis the mammary gland in its mode of activity occupies a position midway between the. Fig. 138.—Section through an alveolus with fat drops in cells. (From Schafer, after von Ebner.) e, cells of alveolus ; k, cells of basement membrane (m); i, connective tissue. sebaceous and submaxillary glands ; some of the cells simply discharging their contents into the lumina, while with others,, the central part of the cell, containing a degenerate daughter nucleus, breaks away and becomes disintegrated, leaving the basal portion still in position. It has already been mentioned that the mammary glands of all Mammals, with the exception of the Monotremes, are usually regarded as being of the nature of modified sebaceous glands. It was partly on account of this belief that certain of the older writers held the view that the secretion of milk was the result of a fatty degeneration leading to a complete disintegration of the secretory cells of the mammary gland.'^ According to this ' Virchow, Die Cellular-Pathologie, Berlin, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marshall, F. H. A. (Francis Hugh Adam), 1878-1949; Cramer, William, 1878-1945; Lochhead, James. London, New York, Longmans, Green
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectreproduction, bookyea
