Herbert Eugene WalterGenetics
[small]Herbert Eugene Walter - Genetics.pdf (6.72 MB)[/small]
[large]http://www.balderexlibris.com/index.php?post/Walter-Herbert-Eugene-Genetics[/large]
PREFACE TO THE THIRD EDITION[/center]
[justify]This book refuses to stay finished, hence after seventeen years a second revision is necessary.
In some fields of human endeavor for which text-books are written, the subject matter may quite suitably be presented in a form comparable to isolated pictures, but the only way to treat correspondingly ·the kaleidoscopic subject of modern Genetics would be to resort to a moving picture apparatus, because the extensions of genetical knowledge are being made so rapidly that even text-book summaries of it demand continuous modification and realignment. The pioneers in Genetics are for the most part not yet historical personages but are still present with us in flesh and blood, so that the student who would study the problems of heredity today can feel all the exhilaration and joy that comes with working at dawn while the day is yet fresh.
On the theoretical side of Genetics within the present generation much of the nature and origin of the germinal determiners has been made out. It is known, for instance, that they are independent enough to be separable at the time of maturation, and transferable in hybridization; that environmental factors, external or internal, may under certain circumstances directly affect them, but that the somatic envelope which encloses the germinal determiners exercises little or no modifying influence upon them.
Probably the surest advance and the greatest conquests in heredity are being made along theoretical rather than so-called practical lines. Nevertheless the lure of possible rewards to be gained from the practical application of newly found genetical facts to the cultivation of plant crops and to the improvement of domestic animals, remains a very great incentive to man, although it must be acknowledged that the exaggerated and baseless hopes accompanying the first flush of the Mendelian renaissance have begun to give way to the more prosaic period of patient and persistent hard work inevitably necessitated in overcomjng unforeseen obstacles to complete success which have arisen in the course of applying the new knowledge.
The incentive to continued effort, even in the face of possible failure, still remains. If by manipulating in any way hereditary genes it is possible to add only a single kernel to the average ear of corn, the potential gain in the United States alone where corn is the principal crop would easily become a matter of millions of dollars. Or in the. same way if in the light of genetical knowledge the wheat crop could be made to ripen on even a single day earlier the resulting conquest in available wheat-producing area would be enormous. Eugenics, or the application of genetical laws to man, is emerging out of the obscuring fogs of speculation and opinion into the light of day as an organized body of substantiated knowledge. In this field of easy prejudices the last word is far from being said. In fact at present the popular impression is general that everyone is talking at once, but nevertheless unmistakable advance is being made. Again, the whole subject of sex, which has been a perennial center of interest for mankind from time immemorial, is proving to be a scientific gold mine to the geneticist who is supposed to approach its theoretical aspects with a cold, unromantic eye. To meet these new advances in the practice and theory of the fundamental laws of Genetics, it has been found necessary to overhaul thoroughly the presentation of the subject in this book. Nearly every page has been modified, conse quently, in some particulars, and considerable additional matter has been supplied, in the hope that the circle of friends who have found the book useful in the past may be retained and enlarged.[/justify]
H.E.W.
PROVIDENCE, R. I.
March, 1930.