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acquired action adaptation ancestors Animal Intelligence animals appetence associated beauty become bees birds body body-cells breed called carbonic acid characters colour complex conceptual consciousness constructs Darwin developed differentiation direct disuse divergence effects eggs elimination embryo emotions example experience explosive fact factor faculty favourable female fertilized gemmules germ germ-plasm germinal cells give rise habits heredity hydra hypothesis individual inference influence inherited insects instinctive activities intelligence intercrossing isolation kinesis kinetic larvae less male mating matter means Mental Evolution metakinesis metakinetic metazoa millimetres mode modified natural selection neurosis object observations offspring organism origin ovum oxygen pain parent perception performed phenomena physiological pleasure probably produced Professor Weismann protoplasm protozoa psychosis question reflex actions regard reproduction resemblance result Romanes seems seen sensations sense sexual sexual selection Sir John Lubbock species sperms stimulus suppose tendency term tion tissues variations
Página 164 - The impression that all this evidence leaves on the mind is one of some wonder whether nurture can do anything at all, beyond giving instruction and professional training.
Página 385 - But pain or suffering of any kind, if long continued, causes depression and lessens the power of action, yet is well adapted to make a creature guard itself against any great or sudden evil. Pleasurable sensations, on the other hand, may be long continued without any depressing effect ; on the contrary, they stimulate the whole system to increased action.
Página 384 - ... beings have been developed through natural selection, or the survival of the fittest, together with use or habit, will admit that these organs have been formed so that their possessors may compete successfully with other beings, and thus increase in number. Now an animal may be led to pursue that course of action which is most beneficial to the species by suffering, such as pain, hunger, thirst, and fear ; or by pleasure, as in eating and drinking, and in the propagation of the species, &c. ;...
Página 72 - Can it, then, be thought improbable, seeing that variations useful to man have undoubtedly occurred, that other variations useful in some way to each being in the great and complex battle of life, should sometimes occur in the course of thousands of generations...
Página 385 - We see this in the pleasure from exertion, even occasionally from great exertion of the body or mind, — in the pleasure of our daily meals, and especially in the pleasure derived from sociability, and from loving our families. The sum of such pleasures as these, which are habitual or frequently recurrent, give, as I can hardly doubt, to most sentient beings an excess of happiness over misery, although many occasionally suffer much.
Página 379 - Under this powerful emotion the action of the heart is much accelerated, or it may be much disturbed. The face reddens, or it becomes purple from the impeded return of the blood, or may turn deadly pale. The respiration is laboured, the chest heaves, and the dilated nostrils quiver. The whole body often trembles. The voice is affected. The teeth are clenched or ground together, and the muscular system is commonly stimulated to violent, almost frantic action. But the gestures of a man in this state...
Página 145 - It is quite conceivable that every species tends to produce varieties of a limited number and kind, and that the effect of natural selection is to favour the development of some of these, while it opposes the development of others along their predetermined lines of modification.
Página 397 - Dogs show what may be fairly called a sense of humour, as distinct from mere play ; if a bit of stick or other such object be thrown to one, he will often carry it away for a short distance ; and then squatting down with it on the ground close before him, will wait until his master comes quite close to take it away. The dog will then seize it and rush away in triumph, repeating the same manoeuvre, and evidently enjoying the practical joke.
Página 200 - While man has only tilled a few level plains, a few great river valleys, a few peninsular mountain slopes, leaving the vast mass of earth untouched by his hand, the insect has spread himself over every land in a thousand shapes, and has made the whole flowering creation subservient to his daily wants. His buttercup, his dandelion, and his meadow-sweet grow thick in every English field. His thyme clothes the hillside; his heather purples the bleak gray moorland.