On certain problems of vertebrate embryology / by John Beard.

  • John Beard
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: On certain problems of vertebrate embryology / by John Beard. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    0 Preface. Twelve months ago, in a paper published in the Ana- tomischer Anzeiger and in the Annals of Botany in con- junction with J. A. Murray, it fell to my lot to point out the bearings of the doctrine of an antithetic alternation of generations (as underlying reproduction and development) on the phenomena of the reduction of the chromosomes during oogenesis and spermatogenesis, and on the meaning of the processes involved in the conjugation of the In- fusoria. Twelve months later circumstances have brought me, in the course of similar enquiries, to an examination of the bearings of this theory on the developmental processes of the higher Vertebrates, the Mammalia and man himself. The rapidity with which the whole series of enquiries, including those into the transient nervous apparatus of various Ichthyopsida and into the history of the yolk-sac and contents, has been, and is being, effected, is more apparent than real. It has, in truth, required eight years of hard work, often performed under discouraging external circumstances, and interrupted by exacting duties, to attain a standpoint
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