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30 Bedford Street Albian American anatomy ancestor animals anomodonts appear Association beds biological birds botany British canal cells Cenomanian characters chlorophyll collection coloured contains Cretaceous DENT & CO deposits described diatom edition eggs eskers evidence evolution experiments fact fauna feet fish Flora foraminifera formation fossils Gault genera genus Geological geologists geology groups illustrated important individual insects interest island J. M. DENT Journal known larva Lepidoptera London Lower male mammals marine matter Museum Natural History Natural Science Natural Selection Naturalist nervure Nymphalids observed obtained occur ontogeny organs origin Palaeozoic paper plants plates post free present Price Prof Professor protoplasm published recent reference regard remarkable result ridges rocks scientific Silurian Sir William Society species specimens Spitsbergen structure text-books theory tion University variations vertebrates volume WILLIAM MARTIN CONWAY zone Zoological zoology
Página 267 - The cat that is clawing all over the box in her impulsive struggle will probably claw the string or loop or button so as to open the door. And gradually all the other non-successful impulses will be stamped out and the particular impulse leading to the successful act will be stamped in by the resulting pleasure, until, after many trials, the cat will, when put in the box, immediately claw the button or loop in a definite way.
Página 144 - NATURE: A Weekly Illustrated Journal of Science. NATURE contains Original Articles on all subjects coming within the domain of Science, contributed by the most eminent Scientists, belonging to all parts of the world. Reviews, setting forth the nature and value of recent Scientific works, are written for NATURE by men who are acknowledged masters in their particular departments.
Página 66 - Published under the direction of the general council of medical education and registration of the United Kingdom, pursuant to the medical act (1858).
Página 266 - When put into the box the cat would show evident signs of discomfort and of an impulse to escape from confinement.
Página 342 - Under changed conditions of life, it is at least possible that slight modifications of instinct might be profitable to a species ; and if it can be shown that instincts do vary ever so little, then I can see no difficulty in natural selection preserving and continually accumulating variations of instinct to any extent that was profitable. It is thus, as I believe, that all the most complex and wonderful instincts have originated.
Página 12 - I'd take it kindly if you'd send the pieces Home to old Missouri I
Página 379 - The properties of substances, though destroyed to sense 'by combination, are not destroyed in reality : it follows from the persistence of force, that the properties of a compound are resultants of the properties of its components — resultants in which the properties of the components are severally in full action, though greatly obscured by each other.
Página 343 - When, at last, the filling was level with the ground, she brought a quantity of fine grains of dirt to the spot and picking up a small pebble in her mandibles, used it as a hammer in pounding them down with rapid strokes, thus making this spot as hard and firm as the surrounding surface.
Página 342 - The general impression that remains with us as a result of our study of these activities is that their complexity and perfection have been greatly overestimated. We have found them in. all stages of development and are convinced that they have passed through many degrees, from the simple to the complex, by the action of natural selection. Indeed, we find in them beautiful examples of the survival of the fittest.