RADIOAUTOGRAPHY 161 



deal with the isotope P^-. Thus its distribution was studied in bones 

 by Dols et al. (1938) and Belanger and Leblond (1946), in tomato 

 fruits by Arnon et al. (1940), in squash plants by Colwell (1942), 

 and in insects by Lindsay and Craig (1942). "Autographs" have 

 been obtained in bone studies with radioactive calcium and strontium 

 by Pecher (1941) and Treadwell et al. (1942). The distribution of 

 radioactive lead in the animal body was investigated by Behrens 

 and Baumann (1933a,b), and thyroid studies were carried out with 

 radioactive iodine by Hamilton et al. ( 1940) , Gorbman and Evans 

 (1941), and Belanger and Leblond (1946). Harrison, Thomas, and 

 Hill ( 1944) employed radioactive sulfur for a radioautograph survey 

 of the distribution of this element in wheat. Many new applications 

 are constantly appearing. 



