INDEX 
21 
References are to pages 
Laboratory study — Continued 
Leaves, arrangement of . 
289 
of moss ........ 
330 
of elms. 
289 
of moth and butterflies . . 
44 
of ferns. 
333 
of nasturtium. 
196 
of grass, shape of 
295 
of pleurococcus. 
305- 
of mosses. 
329 
of protozoa. 
146 
of pine, described . . 
343 
of reptiles. 
106 
of pitcher plant . 
366 
of roots. 
249 
of trees, arrangement of 
289 
of skeleton. 
436 
used for food .... 
292 
of spirogyra. 
307 
used for medicine . 
. . 
292 
of sponge. 
156 
Leaves of beech 
297 
of starfish ....... 
170 
Leech . 
175 
of stems. 
263 
Leeuwenhoek, improver of 
mi- 
of tasting. 
405 
croscope. 
316 
of twigs. 
264 
Legs and wings of birds . 
107, 
108 
of worms. 
180 
Lens of eye ..... 
473 
of yeast plant. 
322 
Lenticels, described . . 
265 
Labrum. 
22 
Leopard frog. 
83 
Lacteals. 
414 
Lepidoptera. 
. 29, 39 
Lactic acid, effect of ... 
314 
Lice. 
. 57, 514 
Ladd, Dr. E. F., quoted . 
506 
Lichens, described . 
325 
La grippe. 
493 
Lichens, action in changing 
Ladybug . 
34 
lava to soil .... 
375 
larvse of.. . 
34 
discussed. 
325 
Ladyslipper. 
396 
epiphytic habit of . 
373 
Lake trout raised in hatcheries 
78 
field study of ... . 
326 
Lampreys. 
, 70 
Life cycle of plants 
221 
Land snail. 
190 
Life history, of ant 
52 
Larch, a conifer. 
345 
of clam. 
188 
use of wood of. 
352 
of eel. 
77 
Large cells, position of, in an¬ 
of fern. 
334 
nual ring .... 
266 
of grasshopper 
25 
Large intestine. 
408 
of house-fly .... 
56 
Lark, meadow, nest of 
J12 
of mosses ..... 
330 
Larkspur, medicinal plant . 
297 
of monarch-butterfly . 
36 
Larva . 
27 
of plant, defined . . . 
221 
Larynx of man. 
445 
of potato-beetle . 
35 
voice box. 
445 
of reptiles. 
99 
Lateral bud. 
264 
of toad. 
93 
Lava, change to soil .... 
375 
Life of flowering plants . 
195 
Layering. 
271 
Life preservers from balsa wood 
356 
Lead, cause of disease . . 
487 
Life processes, of grasshopper . 
19 
Leaf. 
274 
of bacteria. 
310 
of oak. 
297 
Ligaments. 
435 
scars, defined. 
264 
Lily family. 
297 
Leafless plants. 
290 
Lily flower. 
199 
Leaflets of compound leaf . . 
277 
Linden tree. 
364, 
352 
Lean meat, example of protein 
416 
Linen, furnished by flax family 
299 
Leather. 
443 
source of clothing . . 
376 
indirect product of plants 
376 
use of bacteria in manufac- 
made from skins .... 
460 
turing. 
311 
