The general atrophy of old age, as grossly shown by loss of weight, does not proceed equally in all parts of the body. The supporting fibrous tissues of the body and organs certainly atrophy less than the nobler, because actively functional, cells of the organs; it is difficult to estimate the atrophy of the fibrous tissues, for from shrinkage of the parenchyma of organs and of muscles the fibrous framework stands out in greater prominence. Some proliferation or replacement fibrosis follows atrophy of the nobler tissues, and pathologically infection may cause fibrosis. But that the fibrous tissue does to some extent share in the general atrophy is rendered probable on the analogy of the change in the allied tissue of bone which undergoes rarefaction and thinning. The subcutaneous and perivisceral stores of fat diminish out of proportion to the fibrous supporting tissues around them. The place of the fat in the fat cells may be taken by fluid--serous atrophy--or the cells may simply revert to the condition of connective tissue cells. In passing it may be pointed out that it is curious that with the diminished metabolism of old age the stores of fat are not increased as they are in similar circumstances in adult life; Is it due to a widespread atrophy of the connective tissue cells that store fat? If so, an accumulation of fat in the liver might be expected, but this is not so. Possibly it is the result of deficient assimilation. The heart, as Councilman[137] has shown, is on the whole better preserved than the other organs; but it might well be argued that the existence of such a cardiac condition is a determining factor in the attainment of advanced age.