and 3 we show that, in general, there were marked changes from 

 the 5-min to 1-hr films in the two parameters seen in the animals 

 injected in the hind limb (Figs. 1 and 2) . Considering these 

 findings we believe that the faster absorption of sodium diatri- 

 zoate from the neck would result in higher blood levels of this 

 compound and therefore of other drugs with related phar- 

 macokinetics. 



Although the absorption of anv drug from a subcutaneous or 

 intramuscular site depends on its peculiar pharmacologv and the 

 environment at the site, any of the commonly used drugs that are 

 water soluble and do not cause unacceptable tissue damage when 

 injected subcutaneously would be absorbed more rapidly from neck 

 injection sites due to that site's greater vascularity as has 

 been indirectly shown by this studv. Therefore, the choice of 

 the neck as opposed to the limb as an injection site where high 

 levels of therapeutic agents are needed is recommended. 



Unfortunatelv, the urinary tract was not opacified in these 

 animals. This may be due to many factors including inadequate 

 dose, peculiar distribution, and metabolism of contrast material 

 in these animals, and inadequate filming time (though filming was 

 carried out to 2h hr in the preliminary studies with the 

 loggerhead turtles) . 



