14 
INDEX 
References are to pages 
Feeble-mindedness ... 
536 
Fins, of fish. 
. 71, 72 
Feelers, of bullhead .... 
76 
use of, in balancing 
and 
of grasshopper. 
22 
steering. 
72 
Feet of birds, different kinds 
Fires, forests destroyed by 
357. 
, 359 
of. 
108 
prevention of, by national 
Fehling’s solution, formula . 
228 
government 
358 
test for sugar. 
228 
Fireweed in plant succession 
375 
Female strobilus of pine . . 
343 
Firewood, furnished by beech 
Femur, of grasshopper 
24 
family. 
297 
Fennel, member of parsley 
Fireworks, use of spores of club 
family. 
300 
moss in. 
339 
Ferment. 
412 
Firs, conifers. 
345 
Fermentation, cause of . . . 
321 
Fish, care of young 
80 
effect of . 
321 
production .... 
423 
produced by enzymes . 
311 
spawning habits . 
76 
Fern, gametophyte .... 
336 
substitute for meat . 
423 
Fern group, plants belonging to 
333 
summary of ... 
81 
Ferns, example of pterido- 
Fish hatcheries .... 
77 
phytes. 
9 
Fishes, bony. 
. 70, 71 
field study of. 
337 
circulation of . 
75 
habitat of. 
333 
classified. 
9 
laboratory study of. . . . 
337 
food-taking .... 
73 
Ferns and their allies . . 
333 
reproduction of . 
76 
in relation to water .... 
333 
respiration of . . . . 
74 
summary of . ' . 
340 
scales of. 
72 
Fertilization, defined . 91, 165, 
211 
special senses of . 
75 
of egg cell in the ovule . . 
212 
with lungs. 
70 
Fertilized egg cell, beginning 
Fish fry, young .... 
78 
of new organism .... 
153 
yolk, food for. . . . 
76 
of volvox. 
153 
Fission, a form of cell division 
305 
Fertilizers, use of, to supply 
Flaccid cells. 
283 
elements. 
394 
Flagella. 
152 
Fibers in blood. 
451 
Flagellata, group' of Protozoa . 
149 
Fibrinogen, in formation of clot 
451 
Flat worms, classified . . 
• 9, 
175 
Fibrous roots. 
251 
Flavor, of butter . . . 
311 
Fibrovascular bundles, cells of 
266 
Flavors, caused by fermentation 
311 
conducting vessels .... 
248 
by bacteria .... 
311 
in leaves. 
287 
Flax, family. 
299 
structure of. 
266 
useless parts of plant 
re- 
use of, in photosynthesis . 
281 
moved by bacteria . 
311 
Field study, of ferns .... 
337 
Fleas, member of Siphonaptera 
27 
of gymnosperms. 
345 
Flesh-eating animals . 
137 
of insects. 
19 
Fleshy fruits. 
237, 
239 
of moths and butterflies . 
44 
Flicker at suet station 
118 
Field suggestions, mammals 
140 
Flies, carriers of bacteria 
29 
Fig-raising in the U. S. . 
243 
classified. 
. . 9, 29 
Filaments, of gill. 
73 
members of Diptera 
29 
of anthers . 
198 
Flipper of seal .... 
126 
Filtration plants. 
462 
Floods, cause of ... 
348, 351 
Finches, beak of. 
109 
prevention of . 
351 
Finger prints. 
536 
Flour, food elements in . 
426 
