The possession of plasmids was for a long time recognized only in the bacteria. It is now evident that plasmids, or replicative forms of DNA structurally and experimentally comparable to bacterial plasmids, exist in eukaryotic organisms as well. Such plasmids are in fact common among fungi and higher plants. The present review is undertaken to provide a comprehensive account of the data available on plasmids found in eukaryotic organisms. This review will not consider plasmids of prokaryotic origin, even though certain bacterial plasmids, such as the tumor-inducing (Ti) plasmids of...
The possession of plasmids was for a long time recognized only in the bacteria. It is now evident that plasmids, or replicative forms of DNA structura...
Although a human embryo possesses so much grace that the untutored spectator can only admire it in awe, this minute and humble embryo is still almost unknown to many. For some, it seems to belong to the animal kingdom only; others see in it man in his most primordial and elementary aspect. The early life of man thus has become a problem. The development of man as individual (individual development) begins with fertilization. The following pages, therefore, concentrate above all on the develop ment from the ovum to the embryo. The description given below of the ontogenesis of the human embryo...
Although a human embryo possesses so much grace that the untutored spectator can only admire it in awe, this minute and humble embryo is still almost ...
