2 7 8 



INDEX 



Learning, power of, in adults 243 



in children, 243 

 Leaves, old, 35 

 Lens of eye, 190 



growth, 191 



regenerated from retina, 223 

 Leucocytes form nerve cells, 170 

 Levene, P. A. (foot-note), 73 

 Levi, G. (foot-note), 65 

 Lewis, F. T. (foot-note), 77 

 Life, prolongation of, 248 



theory of, viii, 265 

 Life-units, 233 

 Liver, 33 



struggle against connective 



tissue, 33 

 Loeb, J., 211 

 Longevity, 23, 226 



of animals, 264 

 Lucas, F. A., 264 

 Ludwig, Carl, referred to, iii 

 Lungs in old age, 14 



M 



Malaria, 139 

 Mandible in old age, 10 

 Marinesco, 178 

 Martelly (foot-note), 27 

 Maupas, E., 262 

 Memory in old age, 5 

 Metchnikoff, 22, 24, 27, 28, 74 

 Milk, relation to growth, 107 



sour, 28 



Mind in old age, 5 

 Mingazzini, Pio, 211 

 Minot, Charles S., investigations 

 reviewed, v-ix 



point of view, vii 



theory of life, 265 

 Mitotic index, 220 

 Montgomery, T. H. (foot-note), 26 

 Moore, Kathleen (foot-note), 237 

 Morpurgo, B., u 

 Moseley (foot-note), 211 

 Mosso, letter to, iii 

 Miihlmann, 28, 109, 113 



foot-note, no, 128 



Fig. 45, 127 

 M tiller, O. F., 212 

 Muscles in old age, 1 1 



Muscle fibres, differentiation, 62 



growth of, 157 



striated, 63 

 Muscular segment, primitive, 220 



N 



Nageli, 235 



Nauwerck (foot-note), 204 



Necrobiosis, defined, 71 



Necturus, 156 



Nerve cells, adult (Fig. 13), 53 



cerebellar (Fig. 12), 51, 187 



motor, 50 



origin from leucocytes, 1 70 

 Nerves and bone, 32 

 Neurones, 200 

 Notochord, 80 

 Nuclei cause rejuvenation, 166 



differentiation of, 175 



relative increase, 156, 166 



size of, 184 



size reduced, 179 

 Nucleus defined, 41 



growth of, relative, 161 



illustrated, 132 



in secretion, 57 

 Nussbaum, M., 180, 222, 235 



O 



Old age and anatomical quality, 



34 



and organic structure, 34 

 as a disease, 23 

 cause of, 134 

 defined, 84 

 general changes, 21 

 in animals, 30 

 in plants, 34 



medical theories of, 22-30 

 most marked in high animals, 



34 

 period of slowest decline, 5, 



85 



Olmer, 178 

 Oniscus, 207 



Oppenheim (foot-note), 237 

 Organic structure and age, 34 

 Organs, over-living, 214 

 Osier, 23, 245 

 Ost, J., 207 

 Ovum, growth until birth, 129 



