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angles animals appearance arrangement artery Asterolampra Barbadoes Barbadoes deposit Beale become belong binocular blastema body calcareous cartilage cells cellules centre character cilia Closterium Coccus colour connective tissue corpuscles crystals dentine described diameters diatom disc distinct endochrome examination exhibited existence extremity fibrous tissue fluid Foraminifera formed material frond frustules genus germinal matter germinal vesicle glass granular granules Hydrodictyon inch Infusoria instrument Journal layer length less lobes longitudinal magnified margin masses of germinal membrane micro microscope minute molecules muscular fibres nerve fibres nuclei objects observed obtained organs outer oval ovary ovum paper plate portion present processes produced Professor protoplasm puncta rays remarks round sarcode scales seen segments side slides space species specimens sporangium spores stage stellate striae structure substance surface Synapta tentacles tion transparent transverse tubes umbilical lines valve vegetable vesicle vessels Volvox zoospores
Seite 299 - The ordinary notion of species, as assemblages of individuals marked out from each other by definite characters that have been genetically transmitted from original prototypes similarly distinguished, is quite inapplicable to this group...
Seite 43 - The chief point in this application of histology to pathology is to obtain a recognition of the fact, that the cell is really the ultimate morphological element in which there is any manifestation of life, and that we must not transfer the seat of real action to any point beyond the cell.
Seite 291 - It is an astonishing fact that self-fertilisation should not have been an habitual occurrence. It apparently demonstrates to us that there must be something injurious in the process. Nature thus tells us, in the most emphatic manner, that she abhors perpetual self-fertilisation.
Seite 47 - The black pigment-molecules may be diffused throughout the cell or concentrated in a mass, and all kinds of intermediate gradations may exist between diffusion and concentration. The change in colour is owing to these alterations in the molecules, the tint being light when they are concentrated and dark when they are diffused. Mr. Lister ascertained by experiment that their concentration is caused by exposure to the light, by death of the animal, • " On the Cutaneous Pigmentary System of the Frog.
Seite 292 - ... in some way injurious, that some unknown great good is derived from the union of individuals which have been kept distinct for many generations4 ? " This view was supported by observations on plants of other families, eg Papilionaceae ; it could, however, in the absence of experimental proof, be regarded only as a "working hypothesis.
Seite 43 - ... that we must not transfer the seat of real action to any point beyond the cell."* In the attempts which have been made to support this exclusive doctrine, and to give all the tissues and all vital properties a cell origin, the great importance of the molecular element, it seemed to the author, had been strangely overlooked. It becomes important, therefore, to show that real action, both physical and vital, may be seated in minute particles, or molecules much smaller than cells, and that we must...
Seite 47 - Here it cannot be maintained that the results are purely physical, because in different ova we sec such widely varying effects from apparently the same cause. Neither can it be attributed to any direct influence of the cell or of its nucleus, the germinal vesicle. For example, an egg is fully maturated in the female organs of generation, and would prove abortive if a spermatozoid did not find its way through the zona-pellucida and get among the molecules of the yoke.
Seite 89 - OF CONCLUSIONS. In this course of lectures I have endeavoured to prove that the changes which more especially distinguish living structures from lifeless matter, take place in the substance I have termed germinal matter and in this alone. The particles of which this is composed after passing through certain definite stages of existence, undergo conversion into the peculiar substance or substances they were destined to produce. It is the germinal matter alone which is capable of forming, producing,...