FACTS AND FINDINGS 35 



formulations do not actually describe what we see and 

 know. If complete, they would afford a ledger of all the 

 chemical and physical transactions that go on in the body, 

 but that would not describe the organisms' apparently 

 unique qualities as an integrated living individuality, such 

 as the power of enregistering its experiences within itself 

 so that subsequent behavior is influenced. As science is at 

 present, it is necessary to use special biological categories 

 describing the life of the organism — notably its growing, 

 reproducing, developing, varying, endeavoring. For iso- 

 lated transactions in corners of the body, the chemical- 

 physical description may suffice, but not at present for 

 anything like behavior.""^ 



Let us retrace our steps for the moment to the birthday 

 of a single little fruit fly in 1910, which happened to be 

 born with white eyes. We find this seemingly insignificant 

 animal the chief factor in furnishing an impetus toward 

 a study of heredity and genetics, which has brought forth 

 what many biologists consider the nearest approach to the 

 solution of any biological problem yet presented. 



The impetus this solitary fruit fly gave to the study of 

 heredity and genetics, has brought us to the belief that 

 each chromosome is made up, in turn, of a chain of sepa- 

 rate particles which we call "genes," because it seems that 

 they are the very basis on which the genealogy of the 

 individual rests. 



Maybe each chromosone has thousands of these genes, 

 and probably no two are alike. The individual plant or 



