The problem of age, growth, and death; a study of cytomorphosis, based on lectures at the Lowell Institute, March 1907 . bryonic cell does not appear at is a visible differentiation of the orbital-glandcells from the simple stage of the embryonic similar to this can be recognised in thenext of our pictures representing sections of thegland properly known as the pancreas but which issometimes termed the abdominal salivary gland forthe reason that it somewhat resembles the truesalivary. In the cells of the pancreas also we can seethe material which is to produce the sec
The problem of age, growth, and death; a study of cytomorphosis, based on lectures at the Lowell Institute, March 1907 . bryonic cell does not appear at is a visible differentiation of the orbital-glandcells from the simple stage of the embryonic similar to this can be recognised in thenext of our pictures representing sections of thegland properly known as the pancreas but which issometimes termed the abdominal salivary gland forthe reason that it somewhat resembles the truesalivary. In the cells of the pancreas also we can seethe material which is to produce the secretion ac-cumulated in the inner portion of the cell, and whenit is so accumulated the cell appears enlarged in sizeand the nucleus is driven back towards the outer endof the cell where some unaltered protoplasm is also 58 AGE, GROWTH, AND DEATH accumulated (Fig. i6, A^. When this raw material isturned over into secretion by a chemical change, it isdischarged from the cell, the cell loses in volume, and inits shrunken state presents a very different appearance,as is shown at B in the figure. It is necessary for the. Fig. i6. Two Sections of the Pancreatic Gland of a Dog. A, thecells are enlarged by the accumulation of material to form the secretion. B,the cells are shrunk because there has been prolonged secretion and part oftheir substance is lost.—From R. Heidenhain. cells to again elaborate the material for secretion be-fore they can a second time become functionally we have something of the secret of the produc-tion of the various juices in the body revealed to excellent examples of the differentiated con-dition of the cells are afforded us by the examination THE CELLULAR CHANGES OF AGE 59 of hairs, of which I will show you two pictures. The
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