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acid actions adaptation aggregate altered Amphibia animals arise arrangement assimilation atoms become binary compounds body carbonic carbonic acid cause cells changes chemical colloids combination complex compounds conception constituting continuous contrasts creatures crustaceans crystalloids Darwin definite degree differentiation direct displayed distinct divergence effects embryo environment equilibration ethereal waves evidence exhibit exist external extreme facts fertilized germ functions further gamogenesis genesis greater groups growth habitats habitually heat Hence heterogeneity higher Hydrozoa hypothesis of evolution implies incident forces increase individuals Infusoria inorganic kind less living mammals manifest mass ment modes modifications molecular mobility molluscs motion moving equilibrium multiplication muscles natural selection nitrogenous nutriment nutrition offspring organic matter oviparous oxygen parent parthenogenesis peculiarity phenomena physiological units plants polype produced Protozoa races re-actions re-distribution relations result similarly special creations species stamens structure substances successive temperature tion tissues truth types undergo unlike variations Vertebrata vital
Page 264 - I HAVE hitherto sometimes spoken as if the variations — so common and multiform in organic beings under domestication, and in a lesser degree in those in a state of nature — had been due to chance. This, of course, is a wholly incorrect expression, but it serves to acknowledge plainly our ignorance of the cause of each particular variation.
Page 403 - ... would it be too bold to imagine, that all warm-blooded animals have arisen from one living filament, which THE GREAT FIRST CAUSE endued with animality, with the power of acquiring new parts, attended with new propensities, directed by irritations, sensations, volitions, and associations; and thus possessing the faculty of continuing to improve by its own inherent activity-, and of delivering down those improvements by generation to its posterity, world without end!
Page 183 - There seems no alternative but to suppose that the chemical units combine into units immensely more complex than themselves, complex as they are; and that in each organism, the physiological units produced by this further compounding of highly compound atoms, have a more or less distinctive character. We must conclude that in each case, some slight difference of composition in these units, leading to some slight difference in their mutual play of forces, produces a difference in the form which the...
Page 175 - It is a corollary from that primordial truth which, as we have seen, underlies all other truths, that whatever amount of power an organism expends in any shape is the correlate and equivalent of a power that was taken into it from without.
Page 365 - found that in its earliest stage, every organism has the greatest number of characters in common with all other organisms in their earliest stages; that at a stage somewhat later, its structure is like the structures displayed at corresponding phases by a less extensive multitude of organisms; that at each subsequent stage, traits are acquired which successively distinguish the developing embryo from groups of embryos that it previously resembled...
Page 247 - Kentucky, are blind. In some of the crabs the foot-stalk for the eye remains, though the eye is gone ; — the stand for the telescope is there, though the telescope with its glasses has been lost. As it is difficult to imagine that eyes, though useless, could be in any way injurious to animals living in darkness, their loss may be attributed to disuse.
Page 491 - Matter, Motion, and Force are ,but symbols of the Unknown Reality. A Power of which the nature remains for ever inconceivable, and to which no limits in Time or Space can be' imagined, works in us certain effects. These effects have certain likenesses of kind, the most general of which we class together under the names of Matter, Motion, and Force...
Page 400 - This wonderful relationship in the same continent between the dead and the living, will, I do not doubt, hereafter throw more light on the appearance of organic beings on our earth and their disappearance from it than any other class of facts.
Page 403 - The whole train of animated beings, from the simplest and oldest up to the highest and most recent, are, then, to be regarded as a series of advances of the principle of development, which have depended upon external physical circumstances, to which the resulting animals are appropriate.