The American Naturalist, Volume 42Essex Institute, 1908 |
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Página 2
... possible . This procedure proved superior to the first , although the problem involved is somewhat different . At first the large salamander , Spelerpes ruber , was used . This is a terrestrial form . Later the somewhat smaller ...
... possible . This procedure proved superior to the first , although the problem involved is somewhat different . At first the large salamander , Spelerpes ruber , was used . This is a terrestrial form . Later the somewhat smaller ...
Página 3
... possible errors make other cases of doubtful value . The short pieces of grafted bones are often turned obliquely , or even side- wise in the end of the limb , due to the contraction of the skin as the end heals , or to changes that ...
... possible errors make other cases of doubtful value . The short pieces of grafted bones are often turned obliquely , or even side- wise in the end of the limb , due to the contraction of the skin as the end heals , or to changes that ...
Página 4
... possible to detect with greater precision the source of the material for the new bones . The presence of a single bone instead of two as in the former case also simplified the conditions . Despite these advantages , only a few cases ...
... possible to detect with greater precision the source of the material for the new bones . The presence of a single bone instead of two as in the former case also simplified the conditions . Despite these advantages , only a few cases ...
Página 6
possible that the presence of such tissue might excite the leg to regenerate , but this did not prove to be the case . Possibly , here also , the difference in species spoiled the result , but this seems unlikely , since it has been ...
possible that the presence of such tissue might excite the leg to regenerate , but this did not prove to be the case . Possibly , here also , the difference in species spoiled the result , but this seems unlikely , since it has been ...
Página 11
... possible distal structure that exists for this organ . The case is parallel to the formation of a heteromor- phic tail in the earthworm , that develops , as I have shown , from the anterior end of a piece when cut be- hind the level of ...
... possible distal structure that exists for this organ . The case is parallel to the formation of a heteromor- phic tail in the earthworm , that develops , as I have shown , from the anterior end of a piece when cut be- hind the level of ...
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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.