The American Naturalist, Volume 42Essex Institute, 1908 |
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Página 27
... origin to a root , or any rootlets . This comparison shows that the whole plantlet of Cuscuta represents only the stem of the plantlet of Convolvulus . The descriptions which have been given in the preced- ing paragraphs of the ...
... origin to a root , or any rootlets . This comparison shows that the whole plantlet of Cuscuta represents only the stem of the plantlet of Convolvulus . The descriptions which have been given in the preced- ing paragraphs of the ...
Página 32
... origin of their flowering stems from a tuberous or amorphous mass , these plants also resemble the broom rapes ; but in their florescence and fruitage they are very different . They produce no chlorophyl and they are all without either ...
... origin of their flowering stems from a tuberous or amorphous mass , these plants also resemble the broom rapes ; but in their florescence and fruitage they are very different . They produce no chlorophyl and they are all without either ...
Página 48
... origin or continuance . " I have not found any statement by DeVries maintaining that ele- mentary species remain distinct forms from the original stock , when free - crossing with the original stock contin- ues . In my volume on ...
... origin or continuance . " I have not found any statement by DeVries maintaining that ele- mentary species remain distinct forms from the original stock , when free - crossing with the original stock contin- ues . In my volume on ...
Página 58
... origin of coral islands through subsidence of the ocean floor , or the overturning of the earth by worms , or the adaptations of plants to cross - fertilization , or even organic evo- lution , but that they have in mind natural and ...
... origin of coral islands through subsidence of the ocean floor , or the overturning of the earth by worms , or the adaptations of plants to cross - fertilization , or even organic evo- lution , but that they have in mind natural and ...
Página 63
... origin of the metazoan centrosome very much as it was ten years ago . The pioneer work of Schaudinn's upon which this conception of Hartmann and Prowazek's is based has not been fully and satisfactorily confirmed , while much of it has ...
... origin of the metazoan centrosome very much as it was ten years ago . The pioneer work of Schaudinn's upon which this conception of Hartmann and Prowazek's is based has not been fully and satisfactorily confirmed , while much of it has ...
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Termos e frases comuns
AMERICAN NATURALIST Amphibia animals Antedon apotropic appear birds body botanical botanists cause cells cent centrosome changes characters chemical color crinoids described Diplodocus dwarf dwarf faunas Edition eggs embryo endophyte environment evidence evolution experimental experiments fact factors families fasciation fauna female fertilization fishes forms gametes gametophyte genera genus germination give growth haustoria hybrids Illinois important individuals insect investigation isolation known L. H. BAILEY laboratory larvæ latency less living male matter ment method migration mitosis morphological mottled moult mutation nature nerve normal nucleus observations occur oogonium organs origin paper parasites phenogams physiological plants present probably problem produce Professor protoplasm protozoa question radium recent regard regeneration region relation rotifers seed seems sex-tendency somites species specimens spirochetes sporophyte stage Stoma structure substance temperature theory tion tissue trichomes variation vertebrate w[cs zoology
Passagens mais conhecidas
Página 234 - 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.
Página 389 - 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.
Página 389 - 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.
Página 71 - 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.
Página 249 - 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.
Página 389 - 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.
Página 580 - 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.
Página 389 - 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...
Página 117 - ... 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...
Página 696 - In no case may we interpret an action as the outcome of the exercise of a higher psychical faculty if it can be interpreted as the outcome of one which stands lower in the psychological scale.