Pupils, contraction of, 117 Purgatives, 128 Pyelonephritis, 154 Quinquagenarians, diseases of, 140, 145, 156 Rectum, faecal accumulation in, 152 Reflexes, 119 Regression, 122 Rejuvenescence, 10 associated with reproduction, 9, 10, 64 attainment of old age dependent upon, 9, 10 experimental production of, 76, 77 following vasectomy, 78 gland extracts in production of, 12, 73, 80, 81 in animal life, 9, 10 power of reproduction favouring, 23, 24, 69 restricted diet in relation to, 56 testicular grafts producing, 77 Renal inadequacy, 126 Reproductive power, favouring rejuvenescence, 23, 24, 69 waning of, onset of old age following, 26 prolongation of life after waning of, 23 Retas, Joseph, centenarian, 33 Rheumatism, in old age, 44 Rhizomelic spondylitis, 155 Rhondda, Lord, 49 Richardson, B. W., on the duration of life, 18 Rivers, W. H. R., 122 Roberts, W., 154 Robertson and Ray, 12, 60 Rodent ulcer, 143 Roussy, G., 103, 148 Routh, Martin, centenarian, 50 Roy, D., 32, 95 Russian peasants, longevity of, 40 Salimbeni and Gery, 63, 84, 93, 102 Sand, K., 75 Saundby, R., 8, 44, 85 Savage, G., 34 Sclerosis, arterial, 105–107 Mönckeberg’s, 106, 142 spinal, 97 Scrotum, 114 “Second childhood,” 122, 145 Sedatives, 128 Self-preservation, instinct of, 122 Self-reliance, loss of, 48, 49 Seminal tubules, activity and function of, 74 atrophy of, 74, 112, 113 prostatic enlargement following, 112 regeneration of, 74 Senescence, 136 castration not a disposing factor to, 79 causes of, 62–89 Metchnikoff’s theory, 82, 83 pathological, 82 toxaemic, 82 cell changes during, 62–68 in ovaries and testes, 75, 76 colloidal dehydration leading to, 64, 65 diseases associated with, 139 endocrine glands in relation to, 68–81 healthy and morbid, distinction between, 135 nosological compensations of, 140 progress of, 135 rarity of carcinoma in, 87 rejuvenescence necessary to, 10 thyroid deficiency in relation to, 72 _See also_ Longevity; Old age Senile climacteric, 30 Senile type of nanism, 31 Senility, 136 _Senium ex morbo_, 136 Sense organs, impairment and failure of, 117–121 Sensibility to pain, blunting of, 117 Septuagenarians, nervous disease among, 145 pathological old age of, 53 Sex characters, secondary, cause of, 75 following castration, 79 Sex glands, changes in, _climacterium virile_ due to, 27 internal secretion of, 70 Sex incidence of old age, 21, 22 Sexagenarians, diseases common to, 140 nervous disease among, 145 Sexual activity, as manifestation of bodily vigour, 69, 70 duration of, 69 leading to rejuvenescence, 69 waning of, 126 Sexual appetite, on what dependent, 75 perverted, 114 Sexual atrophy, as cause of old age and senility, 69–71