THE CELLULAR BASIS 91 



the result of reasoning about names rather 

 than facts, of getting far from phenomena 

 and philosophizing about them. The compari- 

 son of heredity to the transmission of property 

 from parents to children has produced con- 

 fusion in the scientific as well as in the popu- 

 lar mind. It is only necessary to recall the 

 most elementary facts about development to 

 recognize that in a literal sense developed char- 

 acteristics of parents are never transmitted to 

 children. 



2. The Transmission Hypothesis. — ^And 

 yet the idea that the characteristics of adult 

 persons are transmitted from one generation 

 to the next is a very ancient one and was uni- 

 versally held until the most recent times. Be- 

 fore the details of development were known 

 it was natural to suppose, as Hippocrates did, 

 that white-flowered plants gave rise to white- 

 flowered seeds and that blue-eyed parents pro- 

 duced blue-eyed germs, without attempting to 

 define what was meant by white-flowered seed 

 or blue-eyed germs. And even after the facts 

 of development were fairly well loiown it was 

 generally held that the germ cells were pro- 



