alt()hai)io(;raphy of tissue 



trial x-ray film. The gross autoradiographic 

 result of this exposure of two plant leaves is 

 illustrated in Figure 14. It will be noticed 

 that there is a general darkening over the 

 entire leaf with an increased density at its 

 periphery. In addition, there are small black 

 circular areas of increased grain density that 

 are relatively indistinct. These circular areas 

 of increased grain density suggest that some 

 of the fission products were in the particulate 

 form. 



In order to substantiate the observation 

 regarding specific deposition of particles, 

 additional 1x3 inch plates coated with a 

 100 M NTB^ emulsion and a "T" coat were 

 exposed to portions of the plant leaves for 

 4 days and developed in D-19 developer. 

 These also demonstrated a particle response 

 that was more detailed than that observed 

 with the double-coated x-ray emulsion. The 

 detailed microscopic particle response of 

 fission material on plant leaves is illustrated 

 in Figure 15. In this case the autoradio- 



7 ; \$* 



Fig. 14. Glu^^ auloradiograms of plant leaves 

 following e.xposure by air of the leaves to fission 

 products. An over-all darkening with increased 

 density at the peripher}^ is noticed. Some small 

 circular spot densities can be seen. 



graphic technique demonstrated the presence 

 of particles on lea^'es that was not detectable 

 by routine counting procedures. 



Fig. 13. Stained tissue section of ovary and re- 

 lated tissue adjacent to section used for autoradi- 

 ography of Cs"' in Fig. 12. 



General Discussion 



Up to this point practical problems involv- 

 ing autoradiography have been discussed. 

 ]\Iany specific applications have been 



