202 INDEX 



Loeb, J., 98 

 Loligo, 115 

 Los Angeles, deaths in, 158, 161 



rainfall at, 153 

 Lucretius, 89 

 Lull, R. S., 148 

 Lung-breathing, first recorded, 123 



place of origin of, 121 

 Lung-fishes, 121, 122 



first recorded, 144 

 Lungs, development of, 144 



of higher vertebrates, 120 



origin of, 111 



Maggots, 90 



Magmas, 2, 34, 37, 38, 39, 40, 42, 43, 44 



Maize, 179 



Malaria, 191 



Mammals, 65, 73, 81 



Age of, 46 



archaic, 111, 134, 135, 136, 145 



browsing, origin of, 111 



evolution of, 127, 145 



expansion of, 134 



fate of, 136 



first recorded, 111, 127 



grazing, rise of, 111, 136, 137 



modernized, 135, 145 



modernized, origin of, 111 



modernized, source of, 135 



origin of, 111, 128, 145 



placental, 126 



rise of, 133 

 Man, Age of, 45 



best climatic conditions for, 158 



brute-, 74 



dominance of, over organic world, 

 144, 146 



increase of, dependent on domestic 

 animals, 178 



origin of, 111, 137 



physiological adjustment of, to cli- 

 mate, 156 



reasoning, 74 



Man, response of, to climate, 157, 171 



rise of, 146 

 Mars, 5, 27, 31 



Material resources, as factor in human 

 progress, 147, 151, 152, 154, 155, 

 174, 193 



resources, limited by climate, 155 

 Matter, complexification in, 100 



evolution of, 106 



living, irritability of, 95 

 Matthew, W. D., 117, 184 

 Mayas, 181, 187, 189 

 Mediterranean lands, iron in, 155 



lands, rainfall in, 187, 188 



peoples, 169, 171 



Membranes, extra-embryonal, 126, 128 

 Mental activity, optimum temperature 

 for, 172 



alertness, a manifestation of energy, 

 156 



alertness, effect of lack of material 

 resources on, 150 



capacity, as factor in human prog- 

 ress, 147, 148, 174, 192 

 Mentality, 81 

 Mercury, 28 



Mesopotamia, 179, 181, 182 

 Mesozoic era, 46, 65, 73, 76, 78, 79, 111, 

 132, 133 



era, time ratio of, 69 



sediments, thickness of, 65, 67 

 Meteorites, 33 

 Meteors, 27, 97 

 Miacidse, 136 

 Mice, 90 



Microcosm, organism as, 88 

 Milky Way, 8 

 Millet, 179 

 Mining, 153 

 Miocene time, 46, 111, 136, 138 



time, aridity in, 143, 146 



time, diastrophism in, 142, 146 

 Mississippian period, 46, 76, 79, 111, 

 125, 145 



