The Shipley Collection of Scientific Papers, Volumen231897 |
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Página 895
... tissue no less than the centripetal influence of the surrounding tissues exerted upon the ovum ; of the keimplasm exerted upon the soma no less than of the soma exerted upon the keimplasm , and , in dealing with a portion of the ...
... tissue no less than the centripetal influence of the surrounding tissues exerted upon the ovum ; of the keimplasm exerted upon the soma no less than of the soma exerted upon the keimplasm , and , in dealing with a portion of the ...
Página 24
... tissues and organs . That the rudimentary entoblasts of Aricia , Spio , or Amphitrite are such ancestral rem- iniscences seems almost as clear as that the yolk - sac of the mammalian embryo or the primitive streak of a bird - embryo are ...
... tissues and organs . That the rudimentary entoblasts of Aricia , Spio , or Amphitrite are such ancestral rem- iniscences seems almost as clear as that the yolk - sac of the mammalian embryo or the primitive streak of a bird - embryo are ...
Página 83
... tissue just behind the tip soon ceases to grow , while it undergoes histological differentiation . Is this ces- sation of growth due to the fading out of a growth force due to the remoteness of impregnation ? It is clear that this ...
... tissue just behind the tip soon ceases to grow , while it undergoes histological differentiation . Is this ces- sation of growth due to the fading out of a growth force due to the remoteness of impregnation ? It is clear that this ...
Página 84
... tissue below the tip of the epicotyl ceases to grow - not because there is a necessary limit to growth force at a certain distance from impregna- tion , but because it is advantageous to the species that the individual should cease to ...
... tissue below the tip of the epicotyl ceases to grow - not because there is a necessary limit to growth force at a certain distance from impregna- tion , but because it is advantageous to the species that the individual should cease to ...
Página 2
... tissues have been productive of enormous advances in the understanding of the relation of morbid changes in the body to a great many forms of disease and have brought to light the several phases or varieties of abnormal processes which ...
... tissues have been productive of enormous advances in the understanding of the relation of morbid changes in the body to a great many forms of disease and have brought to light the several phases or varieties of abnormal processes which ...
Términos y frases comunes
American eggs Amphioxus animals annelids appear Appendicularia archenteron Aricia arrangement autotomy axis-cylinder process bones buds cave-earth cavern cell body cell of Helix cell-lineage cells of Invertebrates cellular centrosomes character chromophilous chromophilous granules chromosomes colonial condition curve density depth determined differentiation direction disease distilled water division ecdysis embryo entoblastic evidence existence fact fathoms fibrils FLEMMING'S foliage-leaves function ganglion cells gasteropods geological germ-plasm give granular rows ground-substance growth haematoxylin Heredity hydrometer individual investigation large number latter leaves Leptoplana mesoblast-bands mesoblasts metamorphosis method methylen blue morphological Museum naturalists Nereis nerve cells neuroglia neuroglia fibrils nucleus observations ocean offspring organs origin plant plate polyclade position posterior present primary mesoblasts produce quartet regard reproductive cells safranin segmentation segmentation nucleus slug solution species specimens spindles spiral sporophyll stained stalagmite stem structure substance surface tarsus temperature theory tion tissues variations Vertebrates
Pasajes populares
Página 7 - I happened to read for amusement 'Malthus on Population', and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species. Here then I had at last got a theory by which to work...
Página 2 - And pretty dwarfs to show the way Through fairy hills and fairy dales. But when a bad child goes to bed, From left to right she weaves her rings, And then it dreams all through the night Of only ugly horrid things ! Then lions come with glaring eyes, And tigers growl, a dreadful noise, And ogres draw their cruel knives, To shed the blood of girls and boys.
Página 2 - LITTLE fairy comes at night, Her eyes are blue, her hair is brown, With silver spots upon her wings, And from the moon she flutters down. She has a little silver wand, And when a good child goes to bed She waves her wand from right to left, And makes a circle round its head.
Página 11 - human remains and works of art, such as arrow-heads and knives of flint, occur in all parts of the cave and throughout the entire thickness of the clay : and no distinction founded on condition, distribution, or relative position, can be observed, whereby the human can be separated from the •other reliquiae," which included bones of the "elephant, rhinoceros, ox, deer, horse, bear, hyaena, and a feline animal of large size.
Página 4 - Les noms géographiques des nations qui emploient, dans leur écriture, des caractères latins (langues néo-latines, germaniques, Scandinaves), seront écrits avec l'orthographe de leur pays d'origine. Les règles qui vont suivre s'appliquent uniquement aux noms géographiques de pays qui n'ont point d'écriture propre ou qui écrivent avec des caractères différents des caractères latins. Toutefois, à titre exceptionnel, on conservera l'orthographe usitée pour les noms de lieux, lorsqu'elle...
Página 8 - It may well be doubted ; and yet one is always the better for a walk in the morning air, — a medicine which may be taken over and over again without any sense of sameness, or any failure of its invigorating quality.
Página 12 - Whatever other causes have been at work, natural selection is supreme, to an extent which even Darwin himself hesitated to claim for it. The more we study it the more we are convinced of its overpowering importance, and the more confidently we claim, in Darwin's own words, that it ' has been the most important, but not the exclusive, means of modification...