PART EIGHT 



RADIOBIOLOGY 



Radioactive carbon, with which Dr. Hutchinson treats, 

 was one of the more recent methods for dating objects. His- 

 torians have been aided greatly by data obtained from radio- 

 active carbon. Here the scientist could provide definite data 

 where written records were unavailable. Carbon 14 (radio- 

 active carbon) is a form or isotope of regular carbon 12. In 

 addition to its use as a dater, carbon 14 was used in connec- 

 tion with oxygen as C"'02 to determine some of the inter- 

 mediate steps in photosynthesis. Other isotopes such as P^', 

 S^S Cd^^ and Fe^^ have been used as tracers in plants to study 

 the speed of movement of an absorbed substance and in what 

 parts of the plant they most frequently lodge. It cannot be 

 too strongly emphasized that radiobiology is one of sciences 

 most promising tools. In conclusion, it should be mentioned 

 that medicine has been greatly advanced by the use of tracers. 



Ill 



