FIFTH LECTURE. 



-ooXKo"- 



WEISMANN AND MAUPAS ON THE ORIGIN 



OF DEATH. 



By EDWARD G. GARDINER. 



Heredity and Variation are among the most interest- 

 ing subjects which attract the attention of naturaUsts, 

 and any theory which attempts to explain these phenom- 

 ena is worthy of consideration. 



Why is it that all organisms tend to repeat them- 

 selves in their descendants, and why do the offspring 

 always differ somewhat from their parents ? That this 

 invariably occurs has long been a matter of common 

 knowledge, and yet a satisfactory explanation of why 

 it should occur is still to be sought. 



Darwin founded his theory of evolution on the facts 

 of Heredity and Variation, but the explanation by which 

 he sought to account for these phenomena was offered 

 more as a "provisional hypothesis" than as a com- 

 plete theory. 



Many valuable modifications of, and additions to, his 

 theory have been proposed from time to time by dif- 

 ferent authors, but the main idea of gemmules from all 

 the different cells of the body aggregating in the 



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