Essays upon heredity and kindred biological problems v. 1, 1891, Band 1

Cover
Clarendon Press, 1891
 

Häufige Begriffe und Wortgruppen

Beliebte Passagen

Seite 265 - ... germ-plasm grows, while the latter possessed its characteristic structure from the beginning, viz., before the commencement of growth. But the tendencies of heredity, of which the germplasm is the bearer, depend upon this very molecular structure, and hence only those characters can be transmitted through successive generations which have been previously inherited, viz., those characters which were potentially contained in the structure of the germ-plasm. It also follows that those other characters...
Seite 128 - Worn-out individuals are not only valueless to the species, but they are even harmful, for they take the place of those which are sound.
Seite 17 - I do not however believe in the validity of this explanation ; I consider that death is not a primary necessity, but that it has been secondarily acquired as an adaptation. I believe that life is endowed with a fixed duration, not because it is contrary to its nature to be unlimited, but because the unlimited existence of individuals would be a luxury without any corresponding advantage
Seite 473 - LANE MEDICAL LIBRARY 300 PASTEUR DRIVE PALO ALTO, CALIFORNIA 94304 Ignorance of Library's rules does not exempt violators from penalties.
Seite 162 - highly complex structure conferring upon it the power of developing into a complex organism," and heredity was further explained "by supposing that In each ontogeny a part of the specific germ plasma contained In the parent egg-cell is not used up in the construction of the body of the offspring, but is preserved unchanged for the formation of the germ cells of the following generation.
Seite 67 - There may be in fact cases in which such separation does not take place until after the animal is completely formed, and others, as I believe that I have shown, in which it first arises one or more generations later, viz., in the buds produced by the parent.
Seite 384 - We may therefore broadly conclude that the only circumstance, within the range of those by which persons of similar conditions of life are affected, capable of producing a marked effect on the character of adults, is illness or some accident which causes physical infirmity. The twins who closely resembled each other in childhood and early youth, and were reared under not very dissimilar conditions, either grow unlike through the development of natural charactcristics which had lain dormant at first,...
Seite 89 - Again, talents frequently appear in some single member of a family which has not been previously distinguished. Gauss was not the son of a mathematician; Handel's father was a surgeon, of whose musical powers nothing is known ; Titian was the son and also the nephew of a lawyer, while he and his brother, Francesco Vecellio, were the first painters in a family which produced a succession of seven other artists with diminishing talents. These facts do not, however, prove that the condition of the nerve-tracts...
Seite 103 - In my opinion life became limited in its duration, not because it was contrary to its very nature to be unlimited, but because an unlimited persistence of the individual would be a luxury without a purpose.
Seite 44 - LONGEVITY. — It may be remembered that my nests have enabled me to keep ants under observation for long periods, and that I have identified workers of Lasius niger and Formica fusca which were at least seven years old, and two queens of Formica fusca which have lived with me ever since December 1874. One of these queens, after ailing for some days, died on the soth July, 1887.

Bibliografische Informationen