HEREDITY IO9 



such as land, money, or a house while biological 

 inheritance in such a sense is a figure of speech. 



Some term like heredity became necessary when 

 spontaneous generation was scientifically proved 

 to be untrue as an explanation for the origin of 

 the varied forms of life. So long as man was 

 content to believe that plants and animals might 

 have a varied and independent origin, there was 

 no difliculty in explaining the hereditary peculiari- 

 ties of one of these groups. They simply had 

 them when they were created and this precluded 

 any possibility of tracing their origin. No ex- 

 planation of heredity was possible. 



Whatever may have been the pre-historic or 

 early geologic history of life, the numerous forms 

 of life including man have come into existence 

 according to the law of biogenesis. This necessi- 

 tates that we seek for the origin of all hereditary 

 peculiarities in the ancestors of the forms of life 

 that are being studied. 



We will begin our discussion with a description 

 of the present meaning of heredity. For this pur- 

 pose the human hand miay be considered. In 

 Fig. 38 are shown three hands and there Is no 

 question about their being normal hands. Yet 

 there are distinctive features about each. The 

 hands on either end are the parents and the one 

 in the middle the daughter. It Is to be noted that 

 the mother has a short little finger — about as 



