36 
INDEX 
References are to pages 
Sugar — Continued 
product of photosynthesis . 279 
solution in study of spirogyra 307 
source of. 255, 376 
value of, as food. . . . 440 
Sulphur, a disinfectant . 512 
an element in animal and 
vegetable tissues .... 13 
sulphur dioxide.512 
Summary, of amphibians . . 98 
of arthropods.67 
of bacteria.317 
of birds. 124 
of circulation.465 
of conifers.365 
of digestion of man .... 431 
of disease.495 
of ferns and their allies . . 340 
of fish.81 
of flowering plants .... 302 
of fungi.326 
of hydra-like animals . . 167 
of mammals.139 
of mollusks.194 
of mosses and their allies . . 331 
of nervous system of man . 485 
of our interest in plants . . 397 
of protozoa.150 
of reptiles.106 
of simplest plants . . . . 317 
of skeleton of man . . . . 441 
of spirogyra and pleurococcus 308 
of sponges . - .158 
of starfish group.174 
of worm group.184 
Summer residents, examples of 112 
Sunburn.504 
Sundew, described . . . 289, 367 
rapid movements of . . 367 
sticky substance on leaves . 367 
use of leaves in.367 
Sunfish, care of eggs by . 80 
example of bony fish ... 71 
Sunflower, “ seed ” at feeding 
station for birds . . 117, 119 
Supply of oxygen kept up by 
plants.280 
Surplus food stored in roots 255 
Sutures of bone.434 
Swallows, destroyers of flying 
insects.115 
Swallow-tail butterfly, from 
celery worms.41 
larvae of.41 
Swampy land, reclamation of • 393 
Swarming of bees.48 
Sweat glands, discussed . . . 459 
Sweet, a fundamental taste . . 405 
Swifts, destroyers of flying in¬ 
sects .115 
Swimming pool (public bath) . 517 
Sycamore, useful shade tree . 364 
Symbiosis, defined.158 
example of, lichens .... 325 
nitrogen-gathering bacteria . 258 
Symptoms, medicines in con¬ 
nection with.501 
System (organ). 6 
T 
Tachina fly, beneficial insect . 54 
Tadpole, development of, from 
egg.91 
two stages in.92 
respiration of, by gills ... 92 
stage of frog.92 
Tail region of fish.72 
Talons, characteristic of birds 
of prey.Ill 
Tanning, use of hemlock bark 
in.346 
Tapeworm, a common . . 495 
classified.175 
Tap roots.250 
Tar, source of.346 
Tarsus of grasshopper’s foot 24 
Tartar, effect on gums . . . 407 
Tassel, staminate flower of corn 204 
Taste.472 
Technical names of parts of 
flower. 198-201 
Teeth, of adults.406 
irregular, of children . . . 407 
Telegraph poles, use of gymno- 
sperms for.346 
Temperament, nervous, effect 
of smoking on .... 483 
phlegmatic, effect of smoking 
on.483 
Temperate regions as a habitat 
of evergreens.344 
