Loeb, Jacques (1859-1924), 302 



Loeffler, Friedrich (1852-1915), 240 



Logwood tree, 7 



Longhorn, 7 



Loop of fingerprint, 73 



Lumbering, 582 ff. 



Lungs, 204 ff., 216 



Lymph (limf), 170, 186 f. 



Lymph vessel, 171 



Magic, 328, 329 



Malaria, 6, 177, 244, 371 ; and mosquitoes, 

 621 f., 624 



Malpighi, Marcello (1628-1694), 21, 190 



Mammals, frontispiece, 14, 46; body plan 

 of, 13 ; body pattern of, 48 ; breathing of, 

 211 ; endocrines in, 304 ; reproduction in, 

 379 f. ; reproductive organs in, 382, 383 ; 

 infancy among, 422 f. ; embryo in, 423 f. ; 

 growing periods of, 423 ; classification of, 

 697 ff. 



Mammoth, 57, 456 



Man, limbs of, 46, 49; "transparent", 47; 

 hand of, 50; brain of, 50, 51, 281, 297; 

 chin of, 50, 52 ; and ape, 53 ; uniqueness 

 of, 53 ff. ; characteristics of, 54 ; supe- 

 riority of, 56 ff. ; appendix of, 175 ; meta- 

 morphosis in, 347, 354, 356 ; infancy in, 

 426 f. ; chromosomes in, 491 ; heredity 

 in, 500 ; evolution and, 515 ; and struggle 

 for existence, 553 ff. ; as social organism, 

 554 ; as migrant, 572 ff. ; and balance of 

 nature, 582 ff. ; and birds, 584 ; produc- 

 tion of wealth by, 647 ff. 



Manganese, 103 



Maple, 37 



Margins of leaves, 43 



Marrow of bones, 1 89 



Marsupials (mar su'pi 5lz) , 422, 549, 698 



Marten, 548 



IMass production, 224 



Mayfly, 209 



Measles, 244, 445 



Meats, 125 



INIedulla of adrenals, 307 



Medulla oblongata (me dul'o 6b 'long ga'tfl), 

 283 



Medusa (me du'so), 384 



ISIembranes, 85, 86, 90 ; of embr\'o, 349 



Mendel, Gregor (1822-1884), 474 ff. 



Mental disturbances, 330 



Mercury, poisoning by, 231 

 Merriam, John C. (1869- ), 452 

 Metabolism, 98, 114; and vitamins, 107; 

 , basal, 1 18 ff. ; hormones and rate of, 31 1 f. 

 Metals as occupational hazard, 636 

 Metamorphosis (met a mor'fo sis), in man, 



345, 347, 351, 354, 356; in vertebrates, 



345, 355 ; in insects, 352 f. 

 Metchnikoff (1845-1916), 188 

 Mexican bean beetle, 655 

 Microbes, 342 ; animal, 614 

 Micropyle, 415 

 Microscopes, early, 21 

 Migration, of birds, 179, 181 ; barriers to, 



564 f . ; of man, 586 f . 



Mildews, 371, 689 



Milk, 125 ; production of, 651 



Millepedes, 693 



Milt, 377 



Mind and health, 330 ff. 



Minerals, needs of, 123 ; absorption of, by 



plant, 142 

 Minnow, 357, 360 

 Mites, 616 



Mitosis (mi to'sis), 395 

 Molars, 176 



Molds, 689; water, 24; spores of, 371, 375 

 Mollusks (mol'zfeks), frontispiece, 695; 



shells of, 100 ; balancing organ of, 285 ; 



modification of, 357 

 Mongolian, 63 



Monkeys, 55, 699 ; brain of, 281 

 Monocots, frontispiece, 145, 691 

 Monotremes, 697 

 Moose, 78 



"Moral equivalent of war", 556 

 Morgan, Thomas H. (1866- ), 512 

 Morphin (mor'fin), 231 

 Morphology (morfol'ojT), 458 

 Mosquitoes, and disease, 619 ; and malaria, 



621 ; and yellow fever, 621 ff. 

 Mosses, 371, 689 f. ; life history of, 383 f., 



412 

 Moth, 350; codling, 180; gypsy, 353; 



hawk, 353 

 Motor nerves, 277 

 Mottled teeth, 102 

 Moultings, 350 

 Mouth, of mammals, 14; of insect, 15; 



human, 50 

 Movement, of animals, 17 ; of plants, 17 



713 



