This book deals primarily with changes in the structure of the human and animal body during aging. It is full of pictures showing such changes as can be seen with the electron microscope. Andrew has done much research in this field, not only in the tissues of animals, but in the tissues of aging men. He discusses aging changes in invertebrates and vertebrates. He has given some attention to aging in various groups of living creatures and to a relationship of growth, reproduction, and regenerative capacity to longevity.
As we all know, there is a pigment, lipofuscin, which is found in many cells of aging bodies and tends to increase in amount with age. It appears definitely to have something to do with senescence.
Truex (1940 and 1942) found accumulations of fat in the aging trigeminal ganglion, both in lower mammals and man. Also, nerve cells from a number of