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AMERICAN NATURALIST animals Antedon apogamy apotropic appear become birds blepharoplast body botanical botanists cause cells cent centrosome changes characters chemical chromosomes color complete crinoids described Diplodocus dwarf dwarf faunas eggs embryo endophyte environment evidence evolution experimental experiments fact factors families fasciation fauna female fertilization fishes flower forms fossil fungus gametes gametophyte genera genus germ-cells germination give glands growth haustoria hybrids Illinois important individuals insect investigation isolation known laboratory latency later less male ment method migration mitosis morphological mottled moult mutation nature normal nucleus observations occur oogonium organs origin paper parasites phenogams physiological plants present probably produce Professor protoplasm protozoa question radium reaction recent regard regeneration region relation rotifers seed seems sex-tendency shown somites species specimens spirochetes sporangium sporophyte stage Stoma structure temperature theory tion tissue trichomes variation vertebrate zoology
Strana 242 - In short, we shall have to treat species in the same manner as those naturalists treat genera, who admit that genera are merely artificial combinations made for convenience. This may not be a cheering prospect ; but we shall at least be freed from the vain search for the undiscovered and undiscoverable essence of the term species.
Strana 419 - It is quite true that, to the best of my judgment, the argumentation which applies to brutes holds equally good of men; and, therefore, that all states of consciousness in us, as in them, are immediately caused by molecular changes of the brain-substance.
Strana 419 - The consciousness of brutes would appear to be related to the mechanism of their body simply as a collateral product of its working, and to be as completely without any power of modifying that working, as the steam-whistle which accompanies the work of a locomotive engine is without influence upon its machinery.
Strana 72 - Given any species in any region, the nearest related species is not likely to be found in the same region, nor in a remote region, but in a neighboring district, separated from the first by a barrier of some sort, or at least by a belt of country the breadth of which gives the effect of a barrier.
Strana 259 - 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.
Strana 419 - It seems to me that in men, as in brutes, there is no proof that any state of consciousness is the cause of change in the motion of the matter of the organism.
Strana 638 - Subscription price $6 per year, or 50 cents a number, postage prepaid in the United States; $6.25 to Canada; $6.40 to foreign subscribers of countries in the Postal Union.
Strana 419 - If these positions are well based, it follows that our mental conditions are simply the symbols in consciousness of the changes which take place automatically in the organism...
Strana 119 - ... of individual development had to be taken into account ; and, at present, the study of ancestral evolution introduces a new element of likeness and unlikeness which is not only eminently deserving of recognition, but must ultimately predominate over all others. A classification which shall represent the process of ancestral evolution is, in fact, the end which the labors of the philosophical taxonomist must keep in view. But it is an end which cannot be attained until the progress of palaeontology...