1 ! 



Fig. 34. Radioautographs of adult rat tissues. (1) Cross section through the 

 lower limb (X50). The radiophosphorus is in the diaphysis of the tibia and 

 the fibula. Arrow A points to heavy periosteal layer in the tibia, (i?) Para- 

 median longitudinal section of thoracic vertebra (X50). Arrow B indicates 

 phosphorus deposit in the ossifying neural arch. (5) Cross section of the lower 

 jaw (Xl7). The deposition of radiophosphorus clearly outlines the mandible. 

 In the right portion of the bone an incisor tooth is developing and is also 

 impregnated with the radioactive element. (4) Section of the thyroid from an 

 adult rat (X70), treated with radioiodine. The tracheal cartilage is visible at 

 the bottom of the figure. The thyroid follicles show a reaction due to radio- 

 iodine. Friim Belnnger and Leblond (19.'/i) 



