INDEX 



6ll 



Race improvement, program of 

 eugenics, 576-582 



probabilities, 582-584. 



purposive, 566-587 

 Race suicide, 583 

 Races of men, 157 

 Races, mingling of, 553-565 

 Racial susceptibility, 504 

 Reflex, defined, 247 

 Reflexes, 103, 246, 250-255 



diagrams of, 251, 252 

 Regulation, of blood sugar, 225-227 



of oxygen supply, 232-239 



of temperature, 229-232 



of water content of blood, 227-229 

 Reptiles, age of, ^s 

 Respiration, and oxygen supply, 

 232-239 



origin of, 64 

 Reticulo-endothelial system, 425 

 Righthandedness, 262 

 Rural environment, influence of, 



348-378 



Saint Louis, crimes in, 385 

 Scandinavian-Lapp crosses, 564 

 Schools, conservatism of, 484 

 Science, pure development of, 460, 

 461 



relation to industry, 458-467 

 Semimongoloids, 171 

 Sense organ defined, 247 

 Sex, determination of, 201 



in different populations, 522 

 Sex cleavage, in the community, 267 

 Sex life regulated by marriage, 272- 



275 

 Sex ratio, 276-278 

 Sexes, segregation of, 287 

 Sexual diff"erences, brain weight, 94 



chromosomes, 202 

 Skin, as a protection, 189 

 Skull, evolution of, 88 



racial characters, 161, 162 

 Smallpox, 37, 492 

 Smoke nuisance, 363 

 Societal evolution, 139-154 

 Societies, classification, 141,-143 



contrasted with associations, 142 



hypotheses concerning, 151-154 

 Sodium, increasing in ocean, 49 



proportion to potassium, 47 



Sodium bicarbonate, influence in 



blood, 240-242 

 Solar system, origin of, 26-29 

 Soul, seat of, 114 

 Species and man, 156 

 Spectra, of stars, 4 

 Speech, dominance of, in evolution, 



131-135 



nervous center for, 262 

 Spinal cord, 97 

 Spinal nerves, 102 

 Spontaneous generation, in origin of 



life, 39 

 Stars, age of, 24-29 



gaseous envelopes of, 42 

 Sterilization, of defectives, 513, 577 

 Sugar, and muscular activity, 226 



constancy in blood, 225-227 



storage of, 242 

 Sun, age of, 27-29 



source of ultra-violet light, 9 

 Sunburn, 51 1-5 13 

 Sunlight, physiological effects of, 



269-301 

 Surgery, preventive, 455 

 Sweat glands, function of, 230, 326 

 Syphilis, 445 



Teeth, diseases of, 454 



origin of, 64, 73 

 Temperature, constancy of, 229-232 



necessary for life, 5, 44, 296-299 



physiological effects of, 296-301 

 Testicles, 243 

 Thyroid gland, 243 



disease of, 452 



enlargement of, 346 

 Tissue culture, 210-216 

 Tissue fluid, 220, 223 

 Tobacco, mosaic, 37 

 Trees, influence of, 360 

 Trial and error, 125 

 Trial marriage, 281 

 Tuberculosis, 443-445 



and race mixture, 564 



inheritance of, 495-500 



urban and rural death-rates, 35 1 

 Typhoid fever, 366-368 



Ultra-microscope, 196 

 Ultraviolet light, absorption of, in 

 atmosphere, 9 



