798 Conclusions. Specific and intra-specific selection. Natural selection in the field. Acclimatization. Improvement-selection of sugar-beets by various methods. Rye. Hereditary percentage and centgener power as marks by which intraspecific selection may be guided.
 A. INTRODUCTION
DESCENT: THEORIES OF EVOLUTION AND METHODS OF INVESTIGATION
Newton convinced his contemporaries that natural laws rule the whole universe. Lyell showed, by his principle of slow and gradual evolution, that natural laws have reigned since the beginning of time. To Darwin we owe the almost universal acceptance of the theory of descent.
This doctrine is one of the most noted landmarks in the advance of science. It teaches the validity of natural laws of life in its broadest sense, and crowns the philosophy founded by Newton and Lyell.
Lamarck proposed the hypothesis of a common origin of all living beings and th