. The American journal of anatomy. that in the adult pancreas. Later,in the fifth and sixth month, when the rapid development of the acinusoccurs, the glandular elements surround and enclose the island, and itthen occupies the center of the lobule. The isolated appearance of theislands at this period of separation recalls and seems to support v. Hanse-manns view that the islands develop from the cells of the connective tis-sue. Without the knowledge of the earlier stages of proliferation andtemporary connection with the acinus which I have described, theirisolated position would indeed be inex
. The American journal of anatomy. that in the adult pancreas. Later,in the fifth and sixth month, when the rapid development of the acinusoccurs, the glandular elements surround and enclose the island, and itthen occupies the center of the lobule. The isolated appearance of theislands at this period of separation recalls and seems to support v. Hanse-manns view that the islands develop from the cells of the connective tis-sue. Without the knowledge of the earlier stages of proliferation andtemporary connection with the acinus which I have described, theirisolated position would indeed be inexplicable. From v. Hansemannsdescription, I cannot discover that he studied embryos of a period cor-responding to that represented by Xo. 3 of my series. The advanced vascularization at this stage affords evidence of themanner in which the vessels enter the island. Unlike the glomerulus ofthe kidney, to wliich the island is somewhat analogous owing to its veryrich capillary network, we have not one, but several afferent as well as. FiCx. Pancreas of an embryo of 452 Ilio Islands of Langerhans in the Human Embryo efferent vessels. In those islands still connected with the acinuS;, a vesseldoes not accompany the connecting process of cells. By following an is-land through a series of sections, from four to seven branches, withoutdefinite arrangement however, may be seen entering from the vessels at the periphery anastomose freely and form a network muchricher than that about a glandular structure of equal size. At this periodthe cells between the capillary network of the island assume a definite ar-rangement in columns or rows. If the development here described is comparedwith that observed byLaguesse and by Eenaut, an agreement is found only in. regard to themethod of primary differentiation. These early investigators failed toobserve the stage of the process in which the solid column of cells con-nects the island with its acinus and therefore failed to note the gra
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectanatomy, bookyear1901
