United States or Denmark ? Vote for the TOP Country of the Week !
Presently it came to be known, through the labors of Kolliker, Nageli, Bischoff, and various others, that there are numerous lower forms of animal life which seem to be composed of this sarcode, without any cell wall whatever. The same thing seemed to be true of certain cells of higher organisms, as the blood corpuscles.
Strongly and freely as we have ventured to disagree with Professor Kölliker, we have always done so with regret, and we trust without violating that respect which is due, not only to his scientific eminence and to the careful study which he has devoted to the subject, but to the perfect fairness of his argumentation, and the generous appreciation of the worth of Mr.
But the most elaborate criticisms of the 'Origin of Species' which have appeared are two works of very widely different merit, the one by Professor Kolliker, the well-known anatomist and histologist of Wurzburg; the other by M. Flourens, Perpetual Secretary of the French Academy of Sciences.
The other alternative put by Professor Kolliker the passage of fecundated ova in the course of their development into higher forms would, if it occurred, be merely an extreme case of variation in the Darwinian sense, greater in degree than, but perfectly similar in kind to, that which occurred when the well-known Ancon Ram was developed from an ordinary Ewe's ovum.
The other alternative put by Professor Kolliker the passage of fecundated ova in the course of their development into higher forms would, if it occurred, be merely an extreme case of variation in the Darwinian sense, greater in degree than, but perfectly similar in kind to, that which occurred when the well-known Ancon Ram was developed from an ordinary Ewe's ovum.
It is true that Kolliker says no perfectly decisive fact has been brought forward to prove that the striated muscles contract without having been acted on by nerves. Yet Mr. In the investigation of the nervous system, anatomy and physiology have gone hand in hand.
But gradually the researches of such accurate observers as Unger, Nageli, Kolliker, Reichart, and Remak tended to confirm the opinion of Von Mohl that cells spring only from cells, and finally Rudolf Virchow brought the matter to demonstration about 1860. His Omnis cellula e cellula became from that time one of the accepted data of physiology.
Similarly, von Baer emphasised the idea of an endeavour to realise an aim; von Kölliker, that of “heterogenesis”; Nägeli, that of an impulse towards perfection—all three thus recognising the theory of evolution, but dissenting from the view that the struggle for existence is the impelling factor and actual guide in the process.
If H. Muller and Kolliker can be relied upon, this question is settled by recognizing that a layer of cells, continued from the retina, passes over the surface of the zonula Zinnii, but that no proper nervous element is so prolonged forward. I observe that Kolliker calls the true nervous elements of the retina "the layer of gray cerebral substance."
It will be obvious from what has preceded, that we do not agree with Professor Kölliker in thinking the objections which he brings forward so weighty as to be fatal to Darwin's view. But even if the case were otherwise, we should be unable to accept the "Theory of Heterogeneous Generation" which is offered as a substitute. That theory is thus stated:
Word Of The Day