Humboldt Library of Popular Science Literature, Volume 9

abiogenesis acid action æsthetic animals appear Aristotle beauty become beneath biology birds body brain burrows carbon carbonic acid castings cause caves cells cerned changes character complete consciousness constitution Darwin doctrine doubt dreams earth effect ejected elements ence energy Epictetus eral evolution existence fact feeling functions gemmules gizzards human hypothesis ical idea inches individual inheritance kind knowledge layer leaves less light living Maer Hall mass matter means ment mental Metazoa mind modified motion mould natural selection nature ness objects observation organic origin Origin of Species ovum particles personality petioles phenomena physi physical physiological plants present principle produced protoplasm psychic question regarded remarkable result scientific seen sensations sense side snow species stone structure supposed surface T. H. HUXLEY tain theory thickness things tion true truth uncon whole worms